Manual: lsof
LSOF(8) System Manager's Manual LSOF(8)
NAME
lsof - list open files
SYNOPSIS
lsof [ -?abChHlnNOPQRtUvVX ] [ -A A ] [ -c c ] [ +c c ] [ +|-d d ] [ +|-D D ] [ +|-e s ] [ +|-E ] [
+|-f [cfgGn] ] [ -F [f] ] [ -g [s] ] [ -i [i] ] [ -k k ] [ -K k ] [ +|-L [l] ] [ +|-m m ] [ +|-M ] [
-o [o] ] [ -p s ] [ +|-r [t[m]] ] [ -s [p:s] ] [ -S [t] ] [ -T [t] ] [ -u s ] [ +|-w ] [ -x [fl]
] [ -z [z] ] [ -Z [Z] ] [ -- ] [names]
DESCRIPTION
Lsof revision 4.99.4 lists on its standard output file information about files opened by processes
for the following UNIX dialects:
Apple Darwin 9, Mac OS X 10, macOS 11 and above
FreeBSD 8.2 and above
Linux 2.1.72 and above
NetBSD 1.2 and above
OpenBSD 7.2 and above
Solaris 9, 10 and 11 and above
OpenIndiana 5.11 and above
(See the DISTRIBUTION section of this manual page for information on how to obtain the latest lsof
revision.)
An open file may be a regular file, a directory, a block special file, a character special file, an
executing text reference, a library, a stream or a network file (Internet socket, NFS file or UNIX
domain socket.) A specific file or all the files in a file system may be selected by path.
Instead of a formatted display, lsof will produce output that can be parsed by other programs. See
the -F, option description, and the OUTPUT FOR OTHER PROGRAMS section for more information.
In addition to producing a single output list, lsof will run in repeat mode. In repeat mode it will
produce output, delay, then repeat the output operation until stopped with an interrupt or quit sigā
nal. See the +|-r [t[m]] option description for more information.
OPTIONS
In the absence of any options, lsof lists all open files belonging to all active processes.
If any list request option is specified, other list requests must be specifically requested - e.g.,
if -U is specified for the listing of UNIX socket files, NFS files won't be listed unless -N is also
specified; or if a user list is specified with the -u option, UNIX domain socket files, belonging to
users not in the list, won't be listed unless the -U option is also specified.
Normally, list options that are specifically stated are ORed - i.e., specifying the -i option without
an address and the -ufoo option produces a listing of all network files OR files belonging to
processes owned by user ``foo''. The exceptions are:
1) the `^' (negated) login name or user ID (UID), specified with the -u option;
2) the `^' (negated) process ID (PID), specified with the -p option;
3) the `^' (negated) process group ID (PGID), specified with the -g option;
4) the `^' (negated) command, specified with the -c option;
5) the (`^') negated TCP or UDP protocol state names, specified with the -s [p:s] option.
Since they represent exclusions, they are applied without ORing or ANDing and take effect before any
other selection criteria are applied.
The -a option may be used to AND the selections. For example, specifying -a, -U, and -ufoo produces
a listing of only UNIX socket files that belong to processes owned by user ``foo''.
Caution: the -a option causes all list selection options to be ANDed; it can't be used to cause ANDā
ing of selected pairs of selection options by placing it between them, even though its placement
there is acceptable. Wherever -a is placed, it causes the ANDing of all selection options.
Items of the same selection set - command names, file descriptors, network addresses, process identiā
fiers, user identifiers, zone names, security contexts - are joined in a single ORed set and applied
before the result participates in ANDing. Thus, for example, specifying -i@aaa.bbb, -i@ccc.ddd, -a,
and -ufff,ggg will select the listing of files that belong to either login ``fff'' OR ``ggg'' AND
have network connections to either host aaa.bbb OR ccc.ddd.
Options may be grouped together following a single prefix -- e.g., the option set ``-a -b -C'' may be
stated as -abC. However, since values are optional following +|-f, -F, -g, -i, +|-L, -o, +|-r, -s,
-S, -T, -x and -z. when you have no values for them be careful that the following character isn't
ambiguous. For example, -Fn might represent the -F and -n options, or it might represent the n field
identifier character following the -F option. When ambiguity is possible, start a new option with a
`-' character - e.g., ``-F -n''. If the next option is a file name, follow the possibly ambiguous
option with ``--'' - e.g., ``-F -- name''.
Either the `+' or the `-' prefix may be applied to a group of options. Options that don't take on
separate meanings for each prefix - e.g., -i - may be grouped under either prefix. Thus, for examā
ple, ``+M -i'' may be stated as ``+Mi'' and the group means the same as the separate options. Be
careful of prefix grouping when one or more options in the group does take on separate meanings under
different prefixes - e.g., +|-M; ``-iM'' is not the same request as ``-i +M''. When in doubt, use
separate options with appropriate prefixes.
-? -h These two equivalent options select a usage (help) output list. Lsof displays a shortened
form of this output when it detects an error in the options supplied to it, after it has
displayed messages explaining each error. (Escape the `?' character as your shell reā
quires.)
-a causes list selection options to be ANDed, as described above.
-A A is available on systems configured for AFS whose AFS kernel code is implemented via dynamic
modules. It allows the lsof user to specify A as an alternate name list file where the kerā
nel addresses of the dynamic modules might be found. See the lsof FAQ (The FAQ section
gives its location.) for more information about dynamic modules, their symbols, and how
they affect lsof.
-b causes lsof to avoid kernel functions that might block - lstat(2), readlink(2), and stat(2).
See the BLOCKS AND TIMEOUTS and AVOIDING KERNEL BLOCKS sections for information on using
this option.
-c c selects the listing of files for processes executing the command that begins with the charā
acters of c. Multiple commands may be specified, using multiple -c options. They are
joined in a single ORed set before participating in AND option selection.
If c begins with a `^', then the following characters specify a command name whose processes
are to be ignored (excluded.)
If c begins and ends with a slash ('/'), the characters between the slashes are interpreted
as a regular expression. Shell meta-characters in the regular expression must be quoted to
prevent their interpretation by the shell. The closing slash may be followed by these modiā
fiers:
b the regular expression is a basic one.
i ignore the case of letters.
x the regular expression is an extended one
(default).
See the lsof FAQ (The FAQ section gives its location.) for more information on basic and
extended regular expressions.
The simple command specification is tested first. If that test fails, the command regular
expression is applied. If the simple command test succeeds, the command regular expression
test isn't made. This may result in ``no command found for regex:'' messages when lsof's -V
option is specified.
+c w defines the maximum number of initial characters of the name, supplied by the UNIX dialect,
of the UNIX command associated with a process to be printed in the COMMAND column. (The
lsof default is nine.)
Note that many UNIX dialects do not supply all command name characters to lsof in the files
and structures from which lsof obtains command name. Often dialects limit the number of
characters supplied in those sources. For example, Linux 2.4.27 and Solaris 9 both limit
command name length to 16 characters.
If w is zero ('0'), all command characters supplied to lsof by the UNIX dialect will be
printed.
If w is less than the length of the column title, ``COMMAND'', it will be raised to that
length.
-C disables the reporting of any path name components from the kernel's name cache. See the
KERNEL NAME CACHE section for more information.
+d s causes lsof to search for all open instances of directory s and the files and directories it
contains at its top level. +d does NOT descend the directory tree, rooted at s. The +D D
option may be used to request a full-descent directory tree search, rooted at directory D.
Processing of the +d option does not follow symbolic links within s unless the -x or -x l
option is also specified. Nor does it search for open files on file system mount points on
subdirectories of s unless the -x or -x f option is also specified.
Note: the authority of the user of this option limits it to searching for files that the
user has permission to examine with the system stat(2) function.
-d s specifies a list of file descriptors (FDs) to exclude from or include in the output listing.
The file descriptors are specified in the comma-separated set s - e.g., ``cwd,1,3'',
``^6,^2''. (There should be no spaces in the set.)
The list is an exclusion list if all entries of the set begin with `^'. It is an inclusion
list if no entry begins with `^'. Mixed lists are not permitted.
A file descriptor number range may be in the set as long as neither member is empty, both
members are numbers, and the ending member is larger than the starting one - e.g., ``0-7''
or ``3-10''. Ranges may be specified for exclusion if they have the `^' prefix - e.g.,
``^0-7'' excludes all file descriptors 0 through 7.
Multiple file descriptor numbers are joined in a single ORed set before participating in AND
option selection.
When there are exclusion and inclusion members in the set, lsof reports them as errors and
exits with a non-zero return code.
See the description of File Descriptor (FD) output values in the OUTPUT section for more inā
formation on file descriptor names.
fd is a pseudo file descriptor name for specifying the whole range of possible file descripā
tor numbers. fd does not appear in FD column of output.
+D D causes lsof to search for all open instances of directory D and all the files and directoā
ries it contains to its complete depth.
Processing of the +D option does not follow symbolic links within D unless the -x or -x l
option is also specified. Nor does it search for open files on file system mount points on
subdirectories of D unless the -x or -x f option is also specified.
Note: the authority of the user of this option limits it to searching for files that the
user has permission to examine with the system stat(2) function.
Further note: lsof may process this option slowly and require a large amount of dynamic memā
ory to do it. This is because it must descend the entire directory tree, rooted at D, callā
ing stat(2) for each file and directory, building a list of all the files it finds, and
searching that list for a match with every open file. When directory D is large, these
steps can take a long time, so use this option prudently.
-D D directs lsof's use of the device cache file. The use of this option is sometimes reā
stricted. See the DEVICE CACHE FILE section and the sections that follow it for more inforā
mation on this option.
-D must be followed by a function letter; the function letter may optionally be followed by
a path name. Lsof recognizes these function letters:
? - report device cache file paths
b - build the device cache file
i - ignore the device cache file
r - read the device cache file
u - read and update the device cache file
The b, r, and u functions, accompanied by a path name, are sometimes restricted. When these
functions are restricted, they will not appear in the description of the -D option that acā
companies -h or -? option output. See the DEVICE CACHE FILE section and the sections that
follow it for more information on these functions and when they're restricted.
The ? function reports the read-only and write paths that lsof can use for the device cache
file, the names of any environment variables whose values lsof will examine when forming the
device cache file path, and the format for the personal device cache file path. (Escape the
`?' character as your shell requires.)
When available, the b, r, and u functions may be followed by the device cache file's path.
The standard default is .lsof_hostname in the home directory of the real user ID that exeā
cutes lsof, but this could have been changed when lsof was configured and compiled. (The
output of the -h and -? options show the current default prefix - e.g., ``.lsof''.) The
suffix, hostname, is the first component of the host's name returned by gethostname(2).
When available, the b function directs lsof to build a new device cache file at the default
or specified path.
The i function directs lsof to ignore the default device cache file and obtain its informaā
tion about devices via direct calls to the kernel.
The r function directs lsof to read the device cache at the default or specified path, but
prevents it from creating a new device cache file when none exists or the existing one is
improperly structured. The r function, when specified without a path name, prevents lsof
from updating an incorrect or outdated device cache file, or creating a new one in its
place. The r function is always available when it is specified without a path name arguā
ment; it may be restricted by the permissions of the lsof process.
When available, the u function directs lsof to read the device cache file at the default or
specified path, if possible, and to rebuild it, if necessary. This is the default device
cache file function when no -D option has been specified.
+|-e s exempts the file system whose path name is s from being subjected to kernel function calls
that might block. The +e option exempts stat(2), lstat(2) and most readlink(2) kernel funcā
tion calls. The -e option exempts only stat(2) and lstat(2) kernel function calls. Multiā
ple file systems may be specified with separate +|-e specifications and each may have readā
link(2) calls exempted or not.
This option is currently implemented only for Linux.
CAUTION: this option can easily be mis-applied to other than the file system of interest,
because it uses path name rather than the more reliable device and inode numbers. (Device
and inode numbers are acquired via the potentially blocking stat(2) kernel call and are thus
not available, but see the +|-m m option as a possible alternative way to supply device numā
bers.) Use this option with great care and fully specify the path name of the file system
to be exempted.
When open files on exempted file systems are reported, it may not be possible to obtain all
their information. Therefore, some information columns will be blank, the characters
``UNKN'' preface the values in the TYPE column, and the applicable exemption option is added
in parentheses to the end of the NAME column. (Some device number information might be made
available via the +|-m m option.)
+|-E +E specifies that Linux pipe, Linux UNIX socket, Linux INET(6) socket closed in a local
host, Linux pseudoterminal files, POSIX Message Queueue implementation in Linux, and Linux
eventfd should be displayed with endpoint information and the files of the endpoints should
also be displayed.
Note 1: UNIX socket file endpoint information is only available when the features enabled
line of -v output contains uxsockept, and psudoterminal endpoint information is only availā
able when the features enabled line contains ptyept.
Note 2: POSIX Message Queue file endpoint information is only available when mqueue file
system is mounted.
Pipe endpoint information is displayed in the NAME column in the form ``PID,cmd,FDmode'',
where PID is the endpoint process ID; cmd is the endpoint process command; FD is the endā
point file's descriptor; and mode is the endpoint file's access mode.
Pseudoterminal endpoint information is displayed in the NAME column as
``->/dev/ptsmin PID,cmd,FDmode'' or ``PID,cmd,FDmode''. The first form is for a master deā
vice; the second, for a slave device. min is a slave device's minor device number; and PID,
cmd, FD and mode are the same as with pipe endpoint information. Note: psudoterminal endā
point information is only available when the features enabled line of -v output contains
ptyept. In addition, this feature works on Linux kernels above 4.13.0.
UNIX socket file endpoint information is displayed in the NAME column in the form
``type=TYPE ->INO=INODE PID,cmd,FDmode'', where TYPE is the socket type; INODE is the i-node
number of the connected socket; and PID, cmd, FD and mode are the same as with pipe endpoint
information. Note: UNIX socket file endpoint information is available only when the feaā
tures enabled line of -v output contains uxsockept.
INET socket file endpoint information is inserted to the value at the NAME column in the
form
`` -> PID,cmd,FDmode'', where PID, cmd, FD and mode are the same as with pipe endpoint inā
formation. The endpoint information is available only if the socket is used for local IPC;
both endpoints bind to the same local IPv4 or IPv6 address.
POSIX Message Queue file endpoint information is displayed in the NAME column in the same
form as that of pipe.
eventfd endpoint information is displayed in the NAME column in the same form as that of
pipe. This feature works on Linux kernels above 5.2.0.
Multiple occurrences of this information can appear in a file's NAME column.
-E specifies that endpoint supported files should be displayed with endpoint information,
but not the files of the endpoints.
+|-f [cfgGn]
f by itself clarifies how path name arguments are to be interpreted. When followed by c, f,
g, G, or n in any combination it specifies that the listing of kernel file structure inforā
mation is to be enabled (`+') or inhibited (`-').
Normally a path name argument is taken to be a file system name if it matches a mounted-on
directory name reported by mount(8), or if it represents a block device, named in the mount
output and associated with a mounted directory name. When +f is specified, all path name
arguments will be taken to be file system names, and lsof will complain if any are not.
This can be useful, for example, when the file system name (mounted-on device) isn't a block
device. This happens for some CD-ROM file systems.
When -f is specified by itself, all path name arguments will be taken to be simple files.
Thus, for example, the ``-f -- /'' arguments direct lsof to search for open files with a `/'
path name, not all open files in the `/' (root) file system.
Be careful to make sure +f and -f are properly terminated and aren't followed by a character
(e.g., of the file or file system name) that might be taken as a parameter. For example,
use ``--'' after +f and -f as in these examples.
$ lsof +f -- /file/system/name
$ lsof -f -- /file/name
The listing of information from kernel file structures, requested with the +f [cfgGn] option
form, is normally inhibited, and is not available in whole or part for some dialects - e.g.,
/proc-based Linux kernels below 2.6.22. When the prefix to f is a plus sign (`+'), these
characters request file structure information:
c file structure use count (not Linux)
f file structure address (not Linux)
g file flag abbreviations (Linux 2.6.22 and up)
Abbrev. Flag in C code (see open(2))
W O_WRONLY
RW O_RDWR
CR O_CREAT
EXCL O_EXCL
NTTY O_NOCTTY
TR O_TRUNC
AP O_APPEND
ND O_NDELAY
SYN O_SYNC
ASYN O_ASYNC
DIR O_DIRECT
DTY O_DIRECTORY
NFLK O_NOFOLLOW
NATM O_NOATIME
DSYN O_DSYNC
RSYN O_RSYNC
LG O_LARGEFILE
CX O_CLOEXEC
TMPF O_TMPFILE
G file flags in hexadecimal (Linux 2.6.22 and up)
n file structure node address (not Linux)
When the prefix is minus (`-') the same characters disable the listing of the indicated valā
ues.
File structure addresses, use counts, flags, and node addresses may be used to detect more
readily identical files inherited by child processes and identical files in use by different
processes. Lsof column output can be sorted by output columns holding the values and listed
to identify identical file use, or lsof field output can be parsed by an AWK or Perl
post-filter script, or by a C program.
-F f specifies a character list, f, that selects the fields to be output for processing by anā
other program, and the character that terminates each output field. Each field to be output
is specified with a single character in f. The field terminator defaults to NL, but may be
changed to NUL (000). See the OUTPUT FOR OTHER PROGRAMS section for a description of the
field identification characters and the field output process.
When the field selection character list is empty, all standard fields are selected (except
the raw device field, security context and zone field for compatibility reasons) and the NL
field terminator is used.
When the field selection character list contains only a zero (`0'), all fields are selected
(except the raw device field for compatibility reasons) and the NUL terminator character is
used.
Other combinations of fields and their associated field terminator character must be set
with explicit entries in f, as described in the OUTPUT FOR OTHER PROGRAMS section.
When a field selection character identifies an item lsof does not normally list - e.g.,
PPID, selected with -R - specification of the field character - e.g., ``-FR'' - also selects
the listing of the item.
When the field selection character list contains the single character `?', lsof will display
a help list of the field identification characters. (Escape the `?' character as your shell
requires.)
-g [s] excludes or selects the listing of files for the processes whose optional process group
IDentification (PGID) numbers are in the comma-separated set s - e.g., ``123'' or
``123,^456''. (There should be no spaces in the set.)
PGID numbers that begin with `^' (negation) represent exclusions.
Multiple PGID numbers are joined in a single ORed set before participating in AND option seā
lection. However, PGID exclusions are applied without ORing or ANDing and take effect beā
fore other selection criteria are applied.
The -g option also enables the output display of PGID numbers. When specified without a
PGID set that's all it does.
-H directs lsof to print human readable sizes, e.g. 123.4K 456.7M.
-i [i] selects the listing of files any of whose Internet address matches the address specified in
i. If no address is specified, this option selects the listing of all Internet and x.25
(HP-UX) network files.
If -i4 or -i6 is specified with no following address, only files of the indicated IP verā
sion, IPv4 or IPv6, are displayed. (An IPv6 specification may be used only if the dialects
supports IPv6, as indicated by ``[46]'' and ``IPv[46]'' in lsof's -h or -? output.) Seā
quentially specifying -i4, followed by -i6 is the same as specifying -i, and vice-versa.
Specifying -i4, or -i6 after -i is the same as specifying -i4 or -i6 by itself.
Multiple addresses (up to a limit of 100) may be specified with multiple -i options. (A
port number or service name range is counted as one address.) They are joined in a single
ORed set before participating in AND option selection.
An Internet address is specified in the form (Items in square brackets are optional.):
[46][protocol][@hostname|hostaddr][:service|port]
where:
46 specifies the IP version, IPv4 or IPv6
that applies to the following address.
'6' may be be specified only if the UNIX
dialect supports IPv6. If neither '4' nor
'6' is specified, the following address
applies to all IP versions.
protocol is a protocol name - TCP, UDP or UDPLITE.
hostname is an Internet host name. Unless a
specific IP version is specified, open
network files associated with host names
of all versions will be selected.
hostaddr is a numeric Internet IPv4 address in
dot form; or an IPv6 numeric address in
colon form, enclosed in brackets, if the
UNIX dialect supports IPv6. When an IP
version is selected, only its numeric
addresses may be specified.
service is an /etc/services name - e.g., smtp -
or a list of them.
port is a port number, or a list of them.
IPv6 options may be used only if the UNIX dialect supports IPv6. To see if the dialect supā
ports IPv6, run lsof and specify the -h or -? (help) option. If the displayed description
of the -i option contains ``[46]'' and ``IPv[46]'', IPv6 is supported.
IPv4 host names and addresses may not be specified if network file selection is limited to
IPv6 with -i 6. IPv6 host names and addresses may not be specified if network file selecā
tion is limited to IPv4 with -i 4. When an open IPv4 network file's address is mapped in an
IPv6 address, the open file's type will be IPv6, not IPv4, and its display will be selected
by '6', not '4'.
At least one address component - 4, 6, protocol, hostname, hostaddr, or service - must be
supplied. The `@' character, leading the host specification, is always required; as is the
`:', leading the port specification. Specify either hostname or hostaddr. Specify either
service name list or port number list. If a service name list is specified, the protocol
may also need to be specified if the TCP, UDP and UDPLITE port numbers for the service name
are different. Use any case - lower or upper - for protocol.
Service names and port numbers may be combined in a list whose entries are separated by comā
mas and whose numeric range entries are separated by minus signs. There may be no embedded
spaces, and all service names must belong to the specified protocol. Since service names
may contain embedded minus signs, the starting entry of a range can't be a service name; it
can be a port number, however.
Here are some sample addresses:
-i6 - IPv6 only
TCP:25 - TCP and port 25
@1.2.3.4 - Internet IPv4 host address 1.2.3.4
@[3ffe:1ebc::1]:1234 - Internet IPv6 host address
3ffe:1ebc::1, port 1234
UDP:who - UDP who service port
TCP@lsof.itap:513 - TCP, port 513 and host name lsof.itap
tcp@foo:1-10,smtp,99 - TCP, ports 1 through 10,
service name smtp, port 99, host name foo
tcp@bar:1-smtp - TCP, ports 1 through smtp, host bar
:time - either TCP, UDP or UDPLITE time service port
-K k selects the listing of tasks (threads) of processes, on dialects where task (thread) reportā
ing is supported. (If help output - i.e., the output of the -h or -? options - shows this
option, then task (thread) reporting is supported by the dialect.)
If -K is followed by a value, k, it must be ``i''. That causes lsof to ignore tasks, parā
ticularly in the default, list-everything case when no other options are specified.
When -K and -a are both specified on Linux, and the tasks of a main process are selected by
other options, the main process will also be listed as though it were a task, but without a
task ID. (See the description of the TID column in the OUTPUT section.)
Where the FreeBSD version supports threads, all threads will be listed with their IDs.
In general threads and tasks inherit the files of the caller, but may close some and open
others, so lsof always reports all the open files of threads and tasks.
-k k specifies a kernel name list file, k, in place of /vmunix, /mach, etc. -k is not available
under AIX on the IBM RISC/System 6000.
-l inhibits the conversion of user ID numbers to login names. It is also useful when login
name lookup is working improperly or slowly.
+|-L [l] enables (`+') or disables (`-') the listing of file link counts, where they are available -
e.g., they aren't available for sockets, or most FIFOs and pipes.
When +L is specified without a following number, all link counts will be listed. When -L is
specified (the default), no link counts will be listed.
When +L is followed by a number, only files having a link count less than that number will
be listed. (No number may follow -L.) A specification of the form ``+L1'' will select open
files that have been unlinked. A specification of the form ``+aL1 '' will seā
lect unlinked open files on the specified file system.
For other link count comparisons, use field output (-F) and a post-processing script or proā
gram.
+|-m m specifies an alternate kernel memory file or activates mount table supplement processing.
The option form -m m specifies a kernel memory file, m, in place of /dev/kmem or /dev/mem -
e.g., a crash dump file.
The option form +m requests that a mount supplement file be written to the standard output
file. All other options are silently ignored.
There will be a line in the mount supplement file for each mounted file system, containing
the mounted file system directory, followed by a single space, followed by the device number
in hexadecimal "0x" format - e.g.,
/ 0x801
Lsof can use the mount supplement file to get device numbers for file systems when it can't
get them via stat(2) or lstat(2).
The option form +m m identifies m as a mount supplement file.
Note: the +m and +m m options are not available for all supported dialects. Check the outā
put of lsof's -h or -? options to see if the +m and +m m options are available.
+|-M Enables (+) or disables (-) the reporting of portmapper registrations for local TCP, UDP and
UDPLITE ports, where port mapping is supported. (See the last paragraph of this option deā
scription for information about where portmapper registration reporting is supported.)
The default reporting mode is set by the lsof builder with the HASPMAPENABLED #define in the
dialect's machine.h header file; lsof is distributed with the HASPMAPENABLED #define deactiā
vated, so portmapper reporting is disabled by default and must be requested with +M. Speciā
fying lsof's -h or -? option will report the default mode. Disabling portmapper registraā
tion when it is already disabled or enabling it when already enabled is acceptable. When
portmapper registration reporting is enabled, lsof displays the portmapper registration (if
any) for local TCP, UDP or UDPLITE ports in square brackets immediately following the port
numbers or service names - e.g., ``:1234[name]'' or ``:name[100083]''. The registration inā
formation may be a name or number, depending on what the registering program supplied to the
portmapper when it registered the port.
When portmapper registration reporting is enabled, lsof may run a little more slowly or even
become blocked when access to the portmapper becomes congested or stopped. Reverse the reā
porting mode to determine if portmapper registration reporting is slowing or blocking lsof.
For purposes of portmapper registration reporting lsof considers a TCP, UDP or UDPLITE port
local if: it is found in the local part of its containing kernel structure; or if it is loā
cated in the foreign part of its containing kernel structure and the local and foreign Inā
ternet addresses are the same; or if it is located in the foreign part of its containing
kernel structure and the foreign Internet address is INADDR_LOOPBACK (127.0.0.1). This rule
may make lsof ignore some foreign ports on machines with multiple interfaces when the forā
eign Internet address is on a different interface from the local one.
See the lsof FAQ (The FAQ section gives its location.) for further discussion of portmapper
registration reporting issues.
Portmapper registration reporting is supported only on dialects that have RPC header files.
(Some Linux distributions with GlibC 2.14 do not have them.) When portmapper registration
reporting is supported, the -h or -? help output will show the +|-M option.
-n inhibits the conversion of network numbers to host names for network files. Inhibiting conā
version may make lsof run faster. It is also useful when host name lookup is not working
properly.
-N selects the listing of NFS files.
-o directs lsof to display file offset at all times. It causes the SIZE/OFF output column tiā
tle to be changed to OFFSET. Note: on some UNIX dialects lsof can't obtain accurate or conā
sistent file offset information from its kernel data sources, sometimes just for particular
kinds of files (e.g., socket files.) Consult the lsof FAQ (The FAQ section gives its locaā
tion.) for more information.
The -o and -s options are mutually exclusive; they can't both be specified. When neither is
specified, lsof displays whatever value - size or offset - is appropriate and available for
the type of the file.
-o o defines the number of decimal digits (o) to be printed after the ``0t'' for a file offset
before the form is switched to ``0x...''. An o value of zero (unlimited) directs lsof to
use the ``0t'' form for all offset output.
This option does NOT direct lsof to display offset at all times; specify -o (without a
trailing number) to do that. -o o only specifies the number of digits after ``0t'' in eiā
ther mixed size and offset or offset-only output. Thus, for example, to direct lsof to disā
play offset at all times with a decimal digit count of 10, use:
-o -o 10
or
-oo10
The default number of digits allowed after ``0t'' is normally 8, but may have been changed
by the lsof builder. Consult the description of the -o o option in the output of the -h or
-? option to determine the default that is in effect.
-O directs lsof to bypass the strategy it uses to avoid being blocked by some kernel operations
- i.e., doing them in forked child processes. See the BLOCKS AND TIMEOUTS and AVOIDING KERā
NEL BLOCKS sections for more information on kernel operations that may block lsof.
While use of this option will reduce lsof startup overhead, it may also cause lsof to hang
when the kernel doesn't respond to a function. Use this option cautiously.
-p s excludes or selects the listing of files for the processes whose optional process IDentifiā
cation (PID) numbers are in the comma-separated set s - e.g., ``123'' or ``123,^456''.
(There should be no spaces in the set.)
PID numbers that begin with `^' (negation) represent exclusions.
Multiple process ID numbers are joined in a single ORed set before participating in AND opā
tion selection. However, PID exclusions are applied without ORing or ANDing and take effect
before other selection criteria are applied.
-P inhibits the conversion of port numbers to port names for network files (the mapping is comā
monly learned from /etc/services). Inhibiting the conversion may make lsof run a little
faster. It is also useful when port name lookup is not working properly.
-Q ignore failed search terms. When lsof is told to search for users of a file, or for users of
a device, or for a specific PID, or for certain protocols in use by that PID, and so on,
lsof will return an error if any of the search results are empty. The -Q option will change
this behavior so that lsof will instead return a successful exit code (0) even if any of the
search results are empty. In addition, missing search terms will not be reported to stderr.
+|-r [t[c][m]]
puts lsof in repeat mode. There lsof lists open files as selected by other options, delays
t seconds (default fifteen), then repeats the listing, delaying and listing repetitively unā
til stopped by a condition defined by the prefix to the option.
If the prefix is a `-', repeat mode is endless. Lsof must be terminated with an interrupt
or quit signal. `c' is for specifying the limits of repeating; if the number of iteraā
tions reaches at `', Lsof stops itself.
If the prefix is `+', repeat mode will end the first cycle no open files are listed - and of
course when lsof is stopped with an interrupt or quit signal. When repeat mode ends because
no files are listed, the process exit code will be zero if any open files were ever listed;
one, if none were ever listed.
Lsof marks the end of each listing: if field output is in progress (the -F, option has been
specified), the default marker is `m'; otherwise the default marker is ``========''. The
marker is followed by a NL character.
The optional "m" argument specifies a format for the marker line. The characters
following `m' are interpreted as a format specification to the strftime(3) function, when
both it and the localtime(3) function are available in the dialect's C library. Consult the
strftime(3) documentation for what may appear in its format specification. Note that when
field output is requested with the -F option, cannot contain the NL format, ``%n''.
Note also that when contains spaces or other characters that affect the shell's interā
pretation of arguments, must be quoted appropriately.
Repeat mode reduces lsof startup overhead, so it is more efficient to use this mode than to
call lsof repetitively from a shell script, for example.
To use repeat mode most efficiently, accompany +|-r with specification of other lsof selecā
tion options, so the amount of kernel memory access lsof does will be kept to a minimum.
Options that filter at the process level - e.g., -c, -g, -p, -u - are the most efficient seā
lectors.
Repeat mode is useful when coupled with field output (see the -F, option description) and a
supervising awk or Perl script, or a C program.
-R directs lsof to list the Parent Process IDentification number in the PPID column.
-s [p:s] s alone directs lsof to display file size at all times. It causes the SIZE/OFF output colā
umn title to be changed to SIZE. If the file does not have a size, nothing is displayed.
The optional -s p:s form is available only for selected dialects, and only when the -h or -?
help output lists it.
When the optional form is available, the s may be followed by a protocol name (p), either
TCP or UDP, a colon (`:') and a comma-separated protocol state name list, the option causes
open TCP and UDP files to be excluded if their state name(s) are in the list (s) preceded by
a `^'; or included if their name(s) are not preceded by a `^'.
Dialects that support this option may support only one protocol. When an unsupported protoā
col is specified, a message will be displayed indicating state names for the protocol are
unavailable.
When an inclusion list is defined, only network files with state names in the list will be
present in the lsof output. Thus, specifying one state name means that only network files
with that lone state name will be listed.
Case is unimportant in the protocol or state names, but there may be no spaces and the colon
(`:') separating the protocol name (p) and the state name list (s) is required.
If only TCP and UDP files are to be listed, as controlled by the specified exclusions and
inclusions, the -i option must be specified, too. If only a single protocol's files are to
be listed, add its name as an argument to the -i option.
For example, to list only network files with TCP state LISTEN, use:
-iTCP -sTCP:LISTEN
Or, for example, to list network files with all UDP states except Idle, use:
-iUDP -sUDP:^Idle
State names vary with UNIX dialects, so it's not possible to provide a complete list. Some
common TCP state names are: CLOSED, IDLE, BOUND, LISTEN, ESTABLISHED, SYN_SENT, SYN_RCDV,
ESTABLISHED, CLOSE_WAIT, FIN_WAIT1, CLOSING, LAST_ACK, FIN_WAIT_2, and TIME_WAIT. Two comā
mon UDP state names are Unbound and Idle.
See the lsof FAQ (The FAQ section gives its location.) for more information on how to use
protocol state exclusion and inclusion, including examples.
The -o (without a following decimal digit count) and -s option (without a following protocol
and state name list) are mutually exclusive; they can't both be specified. When neither is
specified, lsof displays whatever value - size or offset - is appropriate and available for
the type of file.
Since some types of files don't have true sizes - sockets, FIFOs, pipes, etc. - lsof disā
plays for their sizes the content amounts in their associated kernel buffers, if possible.
-S [t] specifies an optional time-out seconds value for kernel functions - lstat(2), readlink(2),
and stat(2) - that might otherwise deadlock. The minimum for t is two; the default, fifā
teen; when no value is specified, the default is used.
See the BLOCKS AND TIMEOUTS section for more information.
-T [t] controls the reporting of some TCP/TPI information, also reported by netstat(1), following
the network addresses. In normal output the information appears in parentheses, each item
except TCP or TPI state name identified by a keyword, followed by `=', separated from others
by a single space:
QR=
QS=
SO=
SS=
TF=
WR=
WW=
Not all values are reported for all UNIX dialects. Items values (when available) are reā
ported after the item name and '='.
When the field output mode is in effect (See OUTPUT FOR OTHER PROGRAMS.) each item appears
as a field with a `T' leading character.
-T with no following key characters disables TCP/TPI information reporting.
-T with following characters selects the reporting of specific TCP/TPI information:
f selects reporting of socket options,
states and values, and TCP flags and
values.
q selects queue length reporting.
s selects connection state reporting.
w selects window size reporting.
Not all selections are enabled for some UNIX dialects. State may be selected for all diā
alects and is reported by default. The -h or -? help output for the -T option will show
what selections may be used with the UNIX dialect.
When -T is used to select information - i.e., it is followed by one or more selection charā
acters - the displaying of state is disabled by default, and it must be explicitly selected
again in the characters following -T. (In effect, then, the default is equivalent to -Ts.)
For example, if queue lengths and state are desired, use -Tqs.
Socket options, socket states, some socket values, TCP flags and one TCP value may be reā
ported (when available in the UNIX dialect) in the form of the names that commonly appear
after SO_, so_, SS_, TCP_ and TF_ in the dialect's header files - most often
, and . Consult those header files for
the meaning of the flags, options, states and values.
``SO='' precedes socket options and values; ``SS='', socket states; and ``TF='', TCP flags
and values.
If a flag or option has a value, the value will follow an '=' and the name -- e.g.,
``SO=LINGER=5'', ``SO=QLIM=5'', ``TF=MSS=512''. The following seven values may be reported:
Name
Reported Description (Common Symbol)
KEEPALIVE keep alive time (SO_KEEPALIVE)
LINGER linger time (SO_LINGER)
MSS maximum segment size (TCP_MAXSEG)
PQLEN partial listen queue connections
QLEN established listen queue connections
QLIM established listen queue limit
RCVBUF receive buffer length (SO_RCVBUF)
SNDBUF send buffer length (SO_SNDBUF)
Details on what socket options and values, socket states, and TCP flags and values may be
displayed for particular UNIX dialects may be found in the answer to the ``Why doesn't lsof
report socket options, socket states, and TCP flags and values for my dialect?'' and ``Why
doesn't lsof report the partial listen queue connection count for my dialect?'' questions
in the lsof FAQ (The FAQ section gives its location.) On Linux this option also prints the
state of UNIX domain sockets.
-t produce terse output comprising only process identifiers (without a header), so that it is
easy to use programmatically. e.g.
# reload anything using old SSL
lsof -t /lib/*/libssl.so.* | xargs -r kill -HUP
# get list of processes and then iterate over them (Bash only)
mapfile -t pids < <(
lsof -wt /var/log/your.log
)
for pid in "${pids[@]}" ; do
your_command -p "$pid"
done
The -t option implies the -w option.
-u s selects the listing of files for the user whose login names or user ID numbers are in the
comma-separated set s - e.g., ``abe'', or ``548,root''. (There should be no spaces in the
set.)
Multiple login names or user ID numbers are joined in a single ORed set before participating
in AND option selection.
If a login name or user ID is preceded by a `^', it becomes a negation - i.e., files of
processes owned by the login name or user ID will never be listed. A negated login name or
user ID selection is neither ANDed nor ORed with other selections; it is applied before all
other selections and absolutely excludes the listing of the files of the process. For examā
ple, to direct lsof to exclude the listing of files belonging to root processes, specify
``-u^root'' or ``-u^0''.
-U selects the listing of UNIX domain socket files.
-v selects the listing of lsof version information, including: revision number; when the lsof
binary was constructed; who constructed the binary and where; the name of the compiler used
to construct the lsof binary; the version number of the compiler when readily available; the
compiler and loader flags used to construct the lsof binary; and system information, typiā
cally the output of uname's -a option.
-V directs lsof to indicate the items it was asked to list and failed to find - command names,
file names, Internet addresses or files, login names, NFS files, PIDs, PGIDs, and UIDs.
When other options are ANDed to search options, or compile-time options restrict the listing
of some files, lsof may not report that it failed to find a search item when an ANDed option
or compile-time option prevents the listing of the open file containing the located search
item.
For example, ``lsof -V -iTCP@foobar -a -d 999'' may not report a failure to locate open
files at ``TCP@foobar'' and may not list any, if none have a file descriptor number of 999.
A similar situation arises when HASSECURITY and HASNOSOCKSECURITY are defined at compile
time and they prevent the listing of open files.
+|-w Enables (+) or disables (-) the suppression of warning messages.
The lsof builder may choose to have warning messages disabled or enabled by default. The
default warning message state is indicated in the output of the -h or -? option. Disabling
warning messages when they are already disabled or enabling them when already enabled is acā
ceptable.
The -t option implies the -w option.
-x [fl] may accompany the +d and +D options to direct their processing to cross over symbolic links
and|or file system mount points encountered when scanning the directory (+d) or directory
tree (+D).
If -x is specified by itself without a following parameter, cross-over processing of both
symbolic links and file system mount points is enabled. Note that when -x is specified
without a parameter, the next argument must begin with '-' or '+'.
The optional 'f' parameter enables file system mount point cross-over processing; 'l', symā
bolic link cross-over processing.
The -x option may not be supplied without also supplying a +d or +D option.
-X This is a dialect-specific option.
AIX:
This IBM AIX RISC/System 6000 option requests the reporting of executed text file and shared
library references.
WARNING: because this option uses the kernel readx() function, its use on a busy AIX system
might cause an application process to hang so completely that it can neither be killed nor
stopped. I have never seen this happen or had a report of its happening, but I think there
is a remote possibility it could happen.
By default use of readx() is disabled. On AIX 5L and above lsof may need setuid-root perā
mission to perform the actions this option requests.
The lsof builder may specify that the -X option be restricted to processes whose real UID is
root. If that has been done, the -X option will not appear in the -h or -? help output unā
less the real UID of the lsof process is root. The default lsof distribution allows any UID
to specify -X, so by default it will appear in the help output.
When AIX readx() use is disabled, lsof may not be able to report information for all text
and loader file references, but it may also avoid exacerbating an AIX kernel directory
search kernel error, known as the Stale Segment ID bug.
The readx() function, used by lsof or any other program to access some sections of kernel
virtual memory, can trigger the Stale Segment ID bug. It can cause the kernel's
dir_search() function to believe erroneously that part of an in-memory copy of a file system
directory has been zeroed. Another application process, distinct from lsof, asking the kerā
nel to search the directory - e.g., by using open(2) - can cause dir_search() to loop forā
ever, thus hanging the application process.
Consult the lsof FAQ (The FAQ section gives its location.) and the 00README file of the
lsof distribution for a more complete description of the Stale Segment ID bug, its APAR, and
methods for defining readx() use when compiling lsof.
Linux:
This Linux option requests that lsof skip the reporting of information on all open TCP, UDP
and UDPLITE IPv4 and IPv6 files.
This Linux option is most useful when the system has an extremely large number of open TCP,
UDP and UDPLITE files, the processing of whose information in the /proc/net/tcp* and
/proc/net/udp* files would take lsof a long time, and whose reporting is not of interest.
Use this option with care and only when you are sure that the information you want lsof to
display isn't associated with open TCP, UDP or UDPLITE socket files.
Solaris 10 and above:
This Solaris 10 and above option requests the reporting of cached paths for files that have
been deleted - i.e., removed with rm(1) or unlink(2).
The cached path is followed by the string `` (deleted)'' to indicate that the path by which
the file was opened has been deleted.
Because intervening changes made to the path - i.e., renames with mv(1) or rename(2) - are
not recorded in the cached path, what lsof reports is only the path by which the file was
opened, not its possibly different final path.
-z [z] specifies how Solaris 10 and higher zone information is to be handled.
Without a following argument - e.g., NO z - the option specifies that zone names are to be
listed in the ZONE output column.
The -z option may be followed by a zone name, z. That causes lsof to list only open files
for processes in that zone. Multiple -z z option and argument pairs may be specified to
form a list of named zones. Any open file of any process in any of the zones will be
listed, subject to other conditions specified by other options and arguments.
-Z [Z] specifies how SELinux security contexts are to be handled. It and 'Z' field output characā
ter support are inhibited when SELinux is disabled in the running Linux kernel. See OUTPUT
FOR OTHER PROGRAMS for more information on the 'Z' field output character.
Without a following argument - e.g., NO Z - the option specifies that security contexts are
to be listed in the SECURITY-CONTEXT output column.
The -Z option may be followed by a wildcard security context name, Z. That causes lsof to
list only open files for processes in that security context. Multiple -Z Z option and arguā
ment pairs may be specified to form a list of security contexts. Any open file of any
process in any of the security contexts will be listed, subject to other conditions speciā
fied by other options and arguments. Note that Z can be A:B:C or *:B:C or A:B:* or *:*:C to
match against the A:B:C context.
-- The double minus sign option is a marker that signals the end of the keyed options. It may
be used, for example, when the first file name begins with a minus sign. It may also be
used when the absence of a value for the last keyed option must be signified by the presence
of a minus sign in the following option and before the start of the file names.
names These are path names of specific files to list. Symbolic links are resolved before use.
The first name may be separated from the preceding options with the ``--'' option.
If a name is the mounted-on directory of a file system or the device of the file system,
lsof will list all the files open on the file system. To be considered a file system, the
name must match a mounted-on directory name in mount(8) output, or match the name of a block
device associated with a mounted-on directory name. The +|-f option may be used to force
lsof to consider a name a file system identifier (+f) or a simple file (-f).
If name is a path to a directory that is not the mounted-on directory name of a file system,
it is treated just as a regular file is treated - i.e., its listing is restricted to
processes that have it open as a file or as a process-specific directory, such as the root
or current working directory. To request that lsof look for open files inside a directory
name, use the +d s and +D D options.
If a name is the base name of a family of multiplexed files - e.g, AIX's /dev/pt[cs] - lsof
will list all the associated multiplexed files on the device that are open - e.g.,
/dev/pt[cs]/1, /dev/pt[cs]/2, etc.
If a name is a UNIX domain socket name, lsof will usually search for it by the characters of
the name alone - exactly as it is specified and is recorded in the kernel socket structure.
(See the next paragraph for an exception to that rule for Linux.) Specifying a relative
path - e.g., ./file - in place of the file's absolute path - e.g., /tmp/file - won't work
because lsof must match the characters you specify with what it finds in the kernel UNIX doā
main socket structures.
If a name is a Linux UNIX domain socket name, in one case lsof is able to search for it by
its device and inode number, allowing name to be a relative path. The case requires that
the absolute path -- i.e., one beginning with a slash ('/') be used by the process that creā
ated the socket, and hence be stored in the /proc/net/unix file; and it requires that lsof
be able to obtain the device and node numbers of both the absolute path in /proc/net/unix
and name via successful stat(2) system calls. When those conditions are met, lsof will be
able to search for the UNIX domain socket when some path to it is is specified in name.
Thus, for example, if the path is /dev/log, and an lsof search is initiated when the working
directory is /dev, then name could be ./log.
If a name is none of the above, lsof will list any open files whose device and inode match
that of the specified path name.
If you have also specified the -b option, the only names you may safely specify are file
systems for which your mount table supplies alternate device numbers. See the AVOIDING KERā
NEL BLOCKS and ALTERNATE DEVICE NUMBERS sections for more information.
Multiple file names are joined in a single ORed set before participating in AND option seā
lection.
AFS
Lsof supports the recognition of AFS files for these dialects (and AFS versions):
AIX 4.1.4 (AFS 3.4a)
HP-UX 9.0.5 (AFS 3.4a)
Linux 1.2.13 (AFS 3.3)
Solaris 2.[56] (AFS 3.4a)
It may recognize AFS files on other versions of these dialects, but has not been tested there. Deā
pending on how AFS is implemented, lsof may recognize AFS files in other dialects, or may have diffiā
culties recognizing AFS files in the supported dialects.
Lsof may have trouble identifying all aspects of AFS files in supported dialects when AFS kernel supā
port is implemented via dynamic modules whose addresses do not appear in the kernel's variable name
list. In that case, lsof may have to guess at the identity of AFS files, and might not be able to
obtain volume information from the kernel that is needed for calculating AFS volume node numbers.
When lsof can't compute volume node numbers, it reports blank in the NODE column.
The -A A option is available in some dialect implementations of lsof for specifying the name list
file where dynamic module kernel addresses may be found. When this option is available, it will be
listed in the lsof help output, presented in response to the -h or -?
See the lsof FAQ (The FAQ section gives its location.) for more information about dynamic modules,
their symbols, and how they affect lsof options.
Because AFS path lookups don't seem to participate in the kernel's name cache operations, lsof can't
identify path name components for AFS files.
SECURITY
Lsof has three features that may cause security concerns. First, its default compilation mode allows
anyone to list all open files with it. Second, by default it creates a user-readable and
user-writable device cache file in the home directory of the real user ID that executes lsof. (The
list-all-open-files and device cache features may be disabled when lsof is compiled.) Third, its -k
and -m options name alternate kernel name list or memory files.
Restricting the listing of all open files is controlled by the compile-time HASSECURITY and HASā
NOSOCKSECURITY options. When HASSECURITY is defined, lsof will allow only the root user to list all
open files. The non-root user may list only open files of processes with the same user IDentificaā
tion number as the real user ID number of the lsof process (the one that its user logged on with).
However, if HASSECURITY and HASNOSOCKSECURITY are both defined, anyone may list open socket files,
provided they are selected with the -i option.
When HASSECURITY is not defined, anyone may list all open files.
Help output, presented in response to the -h or -? option, gives the status of the HASSECURITY and
HASNOSOCKSECURITY definitions.
See the Security section of the 00README file of the lsof distribution for information on building
lsof with the HASSECURITY and HASNOSOCKSECURITY options enabled.
Creation and use of a user-readable and user-writable device cache file is controlled by the comā
pile-time HASDCACHE option. See the DEVICE CACHE FILE section and the sections that follow it for
details on how its path is formed. For security considerations it is important to note that in the
default lsof distribution, if the real user ID under which lsof is executed is root, the device cache
file will be written in root's home directory - e.g., / or /root. When HASDCACHE is not defined,
lsof does not write or attempt to read a device cache file.
When HASDCACHE is defined, the lsof help output, presented in response to the -h, -D?, or -? opā
tions, will provide device cache file handling information. When HASDCACHE is not defined, the -h or
-? output will have no -D option description.
Before you decide to disable the device cache file feature - enabling it improves the performance of
lsof by reducing the startup overhead of examining all the nodes in /dev (or /devices) - read the
discussion of it in the 00DCACHE file of the lsof distribution and the lsof FAQ (The FAQ section
gives its location.)
WHEN IN DOUBT, YOU CAN TEMPORARILY DISABLE THE USE OF THE DEVICE CACHE FILE WITH THE -Di OPTION.
When lsof user declares alternate kernel name list or memory files with the -k and -m options, lsof
checks the user's authority to read them with access(2). This is intended to prevent whatever speā
cial power lsof's modes might confer on it from letting it read files not normally accessible via the
authority of the real user ID.
OUTPUT
This section describes the information lsof lists for each open file. See the OUTPUT FOR OTHER PROā
GRAMS section for additional information on output that can be processed by another program.
Lsof only outputs printable (declared so by isprint(3)) 8 bit characters. Non-printable characters
are printed in one of three forms: the C ``\[bfrnt]'' form; the control character `^' form (e.g.,
``^@''); or hexadecimal leading ``\x'' form (e.g., ``\xab''). Space is non-printable in the COMMAND
column (``\x20'') and printable elsewhere.
For some dialects - if HASSETLOCALE is defined in the dialect's machine.h header file - lsof will
print the extended 8 bit characters of a language locale. The lsof process must be supplied a lanā
guage locale environment variable (e.g., LANG) whose value represents a known language locale in
which the extended characters are considered printable by isprint(3). Otherwise lsof considers the
extended characters non-printable and prints them according to its rules for non-printable characā
ters, stated above. Consult your dialect's setlocale(3) man page for the names of other environment
variables that may be used in place of LANG - e.g., LC_ALL, LC_CTYPE, etc.
Lsof's language locale support for a dialect also covers wide characters - e.g., UTF-8 - when HASSETā
LOCALE and HASWIDECHAR are defined in the dialect's machine.h header file, and when a suitable lanā
guage locale has been defined in the appropriate environment variable for the lsof process. Wide
characters are printable under those conditions if iswprint(3) reports them to be. If HASSETLOCALE,
HASWIDECHAR and a suitable language locale aren't defined, or if iswprint(3) reports wide characters
that aren't printable, lsof considers the wide characters non-printable and prints each of their 8
bits according to its rules for non-printable characters, stated above.
Consult the answers to the "Language locale support" questions in the lsof FAQ (The FAQ section gives
its location.) for more information.
Lsof dynamically sizes the output columns each time it runs, guaranteeing that each column is a miniā
mum size. It also guarantees that each column is separated from its predecessor by at least one
space.
COMMAND contains the first nine characters of the name of the UNIX command associated with the
process. If a non-zero w value is specified to the +c w option, the column contains the
first w characters of the name of the UNIX command associated with the process up to the
limit of characters supplied to lsof by the UNIX dialect. (See the description of the +c
w command or the lsof FAQ for more information. The FAQ section gives its location.)
If w is less than the length of the column title, ``COMMAND'', it will be raised to that
length.
If a zero w value is specified to the +c w option, the column contains all the characters
of the name of the UNIX command associated with the process.
All command name characters maintained by the kernel in its structures are displayed in
field output when the command name descriptor (`c') is specified. See the OUTPUT FOR
OTHER COMMANDS section for information on selecting field output and the associated comā
mand name descriptor.
PID is the Process IDentification number of the process.
TID is the task (thread) IDentification number, if task (thread) reporting is supported by the
dialect and a task (thread) is being listed. (If help output - i.e., the output of the -h
or -? options - shows this option, then task (thread) reporting is supported by the diā
alect.)
A blank TID column in Linux indicates a process - i.e., a non-task.
TASKCMD is the task command name. Generally this will be the same as the process named in the
COMMAND column, but some task implementations (e.g., Linux) permit a task to change its
command name.
The TASKCMD column width is subject to the same size limitation as the COMMAND column.
ZONE is the Solaris 10 and higher zone name. This column must be selected with the -z option.
SECURITY-CONTEXT
is the SELinux security context. This column must be selected with the -Z option. Note
that the -Z option is inhibited when SELinux is disabled in the running Linux kernel.
PPID is the Parent Process IDentification number of the process. It is only displayed when the
-R option has been specified.
PGID is the process group IDentification number associated with the process. It is only disā
played when the -g option has been specified.
USER is the user ID number or login name of the user to whom the process belongs, usually the
same as reported by ps(1). However, on Linux USER is the user ID number or login that
owns the directory in /proc where lsof finds information about the process. Usually that
is the same value reported by ps(1), but may differ when the process has changed its efā
fective user ID. (See the -l option description for information on when a user ID number
or login name is displayed.)
FD is the File Descriptor number of the file or:
cwd current working directory;
Lnn library references (AIX);
ctty character tty;
DEL deleted file;
err FD information error (see NAME column);
fp. Fileport (Darwin);
jld jail directory (FreeBSD);
ltx shared library text (code and data);
Mxx hex memory-mapped type number xx.
m86 DOS Merge mapped file;
mem memory-mapped file;
mmap memory-mapped device;
NOFD for a Linux /proc//fd directory that can't be opened --
the directory path appears in the NAME column, followed by an error
message;
pd parent directory;
Rnn unknown pregion number (HP-UX);
rtd root directory;
twd per task current working directory;
txt program text (code and data);
v86 VP/ix mapped file;
FD is followed by one of these characters, describing the mode under which the file is
open:
r for read access;
w for write access;
u for read and write access;
space if mode unknown and no lock
character follows;
`-' if mode unknown and lock
character follows.
The mode character is followed by one of these lock characters, describing the type of
lock applied to the file:
N for a Solaris NFS lock of unknown type;
r for read lock on part of the file;
R for a read lock on the entire file;
w for a write lock on part of the file;
W for a write lock on the entire file;
u for a read and write lock of any length;
U for a lock of unknown type;
x for an SCO OpenServer Xenix lock on part of the file;
X for an SCO OpenServer Xenix lock on the entire file;
space if there is no lock.
See the LOCKS section for more information on the lock information character.
The FD column contents constitutes a single field for parsing in post-processing scripts.
FD numbers larger than 9999 are abbreviated to a ``*'' followed by the last three digits.
E.g., 10001 appears as ``*001''
TYPE is the type of the node associated with the file - e.g., VDIR, VREG, etc.
or ``ax25'' for a Linux AX.25 socket;
or ``a_inode'' for anonymous inode;
or ``icmp'' for an ICMP socket;
or ``inet'' for an Internet domain socket;
or ``ipx'' for an IPX socket;
or ``key'' for an internal key management socket;
or ``lla'' for a HP-UX link level access file;
or ``ndrv'' for a net driver socket;
or ``netlink'' for a netlink socket;
or ``pack'' for a packet socket;
or ``ppp'' for a PPP socket;
or ``raw'' for a raw socket;
or ``raw6'' for a raw IPv6 socket;
or ``rte'' for an AF_ROUTE socket;
or ``sock'' for a socket of unknown domain;
or ``systm'' for a system socket;
or ``unix'' for a UNIX domain socket;
or ``x.25'' for an HP-UX x.25 socket;
or ``ATALK'' for an AppleTalk socket;
or ``BLK'' for a block special file;
or ``CHR'' for a character special file;
or ``DEL'' for a Linux map file that has been deleted;
or ``DIR'' for a directory;
or ``DOOR'' for a VDOOR file;
or ``EVENTFD'' for an eventfd;
or ``FIFO'' for a FIFO special file;
or ``FSEVENTS'' for fsevents;
or ``IPv4'' for an IPv4 socket;
or ``IPv6'' for an open IPv6 network file - even if its address is IPv4, mapped in an IPv6
address;
or ``KQUEUE'' for a BSD style kernel event queue file;
or ``LINK'' for a symbolic link file;
or ``MPB'' for a multiplexed block file;
or ``MPC'' for a multiplexed character file;
or ``PAS'' for a /proc/as file;
or ``PAXV'' for a /proc/auxv file;
or ``PCRE'' for a /proc/cred file;
or ``PCTL'' for a /proc control file;
or ``PCUR'' for the current /proc process;
or ``PCWD'' for a /proc current working directory;
or ``PDIR'' for a /proc directory;
or ``PETY'' for a /proc executable type (etype);
or ``PFD'' for a /proc file descriptor;
or ``PFDR'' for a /proc file descriptor directory;
or ``PFIL'' for an executable /proc file;
or ``PFPR'' for a /proc FP register set;
or ``PGD'' for a /proc/pagedata file;
or ``PGID'' for a /proc group notifier file;
or ``PIPE'' for pipes;
or ``PLC'' for a /proc/lwpctl file;
or ``PLDR'' for a /proc/lpw directory;
or ``PLDT'' for a /proc/ldt file;
or ``PLPI'' for a /proc/lpsinfo file;
or ``PLST'' for a /proc/lstatus file;
or ``PLU'' for a /proc/lusage file;
or ``PLWG'' for a /proc/gwindows file;
or ``PLWI'' for a /proc/lwpsinfo file;
or ``PLWS'' for a /proc/lwpstatus file;
or ``PLWU'' for a /proc/lwpusage file;
or ``PLWX'' for a /proc/xregs file;
or ``PMAP'' for a /proc map file (map);
or ``PMPS'' for a /proc/maps file;
or ``PMEM'' for a /proc memory image file;
or ``PNTF'' for a /proc process notifier file;
or ``POBJ'' for a /proc/object file;
or ``PODR'' for a /proc/object directory;
or ``POLP'' for an old format /proc light weight process file;
or ``POPF'' for an old format /proc PID file;
or ``POPG'' for an old format /proc page data file;
or ``PORT'' for a SYSV named pipe;
or ``PREG'' for a /proc register file;
or ``PRMP'' for a /proc/rmap file;
or ``PROCDSC'' for a processor descriptor;
or ``PRTD'' for a /proc root directory;
or ``PSGA'' for a /proc/sigact file;
or ``PSIN'' for a /proc/psinfo file;
or ``PSTA'' for a /proc status file;
or ``PSXMQ'' for a POSIX message queue file;
or ``PSXSEM'' for a POSIX semaphore file;
or ``PSXSHM'' for a POSIX shared memory file;
or ``PTS'' for a /dev/pts file;
or ``PUSG'' for a /proc/usage file;
or ``PW'' for a /proc/watch file;
or ``PXMP'' for a /proc/xmap file;
or ``REG'' for a regular file;
or ``SHM'' for a shared memory file;
or ``SMT'' for a shared memory transport file;
or ``STR'' for streams;
or ``STSO'' for a stream socket;
or ``UNKN'' for an unknown file;
or ``UNKNcwd'' for unknown current working directory;
or ``UNKNdel'' for unknown deleted file;
or ``UNKNfd'' for unknown file descriptor;
or ``UNKNmem'' for unknown memory-mapped file;
or ``UNKNrtd'' for unknown root directory;
or ``UNKNtxt'' for unknown program text;
or ``UNNM'' for an unnamed type file;
or ``XNAM'' for an OpenServer Xenix special file of unknown type;
or ``XSEM'' for an OpenServer Xenix semaphore file;
or ``XSD'' for an OpenServer Xenix shared data file;
or ``UNSP'' for an unsupported file;
or the four type number octets if the corresponding name isn't known.
FILE-ADDR contains the kernel file structure address when f has been specified to +f;
FCT contains the file reference count from the kernel file structure when c has been specified
to +f;
FILE-FLAG when g or G has been specified to +f, this field contains the contents of the f_flag[s]
member of the kernel file structure and the kernel's per-process open file flags (if
available); `G' causes them to be displayed in hexadecimal; `g', as short-hand names; two
lists may be displayed with entries separated by commas, the lists separated by a semiā
colon (`;'); the first list may contain short-hand names for f_flag[s] values from the
following table:
AIO asynchronous I/O (e.g., FAIO)
AP append
ASYN asynchronous I/O (e.g., FASYNC)
BAS block, test, and set in use
BKIU block if in use
BL use block offsets
BSK block seek
CA copy avoid
CIO concurrent I/O
CLON clone
CLRD CL read
CR create
DF defer
DFI defer IND
DFLU data flush
DIR direct
DLY delay
DOCL do clone
DSYN data-only integrity
DTY must be a directory
EVO event only
EX open for exec
EXCL exclusive open
FSYN synchronous writes
GCDF defer during unp_gc() (AIX)
GCMK mark during unp_gc() (AIX)
GTTY accessed via /dev/tty
HUP HUP in progress
KERN kernel
KIOC kernel-issued ioctl
LCK has lock
LG large file
MBLK stream message block
MK mark
MNT mount
MSYN multiplex synchronization
NATM don't update atime
NB non-blocking I/O
NBDR no BDRM check
NBIO SYSV non-blocking I/O
NBF n-buffering in effect
NC no cache
ND no delay
NDSY no data synchronization
NET network
NFLK don't follow links
NMFS NM file system
NOTO disable background stop
NSH no share
NTTY no controlling TTY
OLRM OLR mirror
PAIO POSIX asynchronous I/O
PATH path
PP POSIX pipe
R read
RC file and record locking cache
REV revoked
RSH shared read
RSYN read synchronization
RW read and write access
SL shared lock
SNAP cooked snapshot
SOCK socket
SQSH Sequent shared set on open
SQSV Sequent SVM set on open
SQR Sequent set repair on open
SQS1 Sequent full shared open
SQS2 Sequent partial shared open
STPI stop I/O
SWR synchronous read
SYN file integrity while writing
TCPM avoid TCP collision
TMPF temporary file
TR truncate
W write
WKUP parallel I/O synchronization
WTG parallel I/O synchronization
VH vhangup pending
VTXT virtual text
XL exclusive lock
this list of names was derived from F* #define's in dialect header files ,
, , , and ; see the common.h header
file for a list showing the correspondence between the above short-hand names and the
header file definitions;
the second list (after the semicolon) may contain short-hand names for kernel per-process
open file flags from this table:
ALLC allocated
BR the file has been read
BHUP activity stopped by SIGHUP
BW the file has been written
CLSG closing
CX close-on-exec (see fcntl(F_SETFD))
LCK lock was applied
MP memory-mapped
OPIP open pending - in progress
RSVW reserved wait
SHMT UF_FSHMAT set (AIX)
USE in use (multi-threaded)
NODE-ID (or INODE-ADDR for some dialects) contains a unique identifier for the file node (usually
the kernel vnode or inode address, but also occasionally a concatenation of device and
node number) when n has been specified to +f;
DEVICE contains the device numbers, separated by commas, for a character special, block special,
regular, directory or NFS file;
or ``memory'' for a memory file system node under Tru64 UNIX;
or the address of the private data area of a Solaris socket stream;
or a kernel reference address that identifies the file (The kernel reference address may
be used for FIFO's, for example.);
or the base address or device name of a Linux AX.25 socket device.
Usually only the lower thirty two bits of Tru64 UNIX kernel addresses are displayed.
SIZE, SIZE/OFF, or OFFSET
is the size of the file or the file offset in bytes. A value is displayed in this column
only if it is available. Lsof displays whatever value - size or offset - is appropriate
for the type of the file and the version of lsof.
On some UNIX dialects lsof can't obtain accurate or consistent file offset information
from its kernel data sources, sometimes just for particular kinds of files (e.g., socket
files.) In other cases, files don't have true sizes - e.g., sockets, FIFOs, pipes - so
lsof displays for their sizes the content amounts it finds in their kernel buffer descripā
tors (e.g., socket buffer size counts or TCP/IP window sizes.) Consult the lsof FAQ (The
FAQ section gives its location.) for more information.
The file size is displayed in decimal; the offset is normally displayed in decimal with a
leading ``0t'' if it contains 8 digits or less; in hexadecimal with a leading ``0x'' if it
is longer than 8 digits. (Consult the -o o option description for information on when 8
might default to some other value.)
Thus the leading ``0t'' and ``0x'' identify an offset when the column may contain both a
size and an offset (i.e., its title is SIZE/OFF).
If the -o option is specified, lsof always displays the file offset (or nothing if no offā
set is available) and labels the column OFFSET. The offset always begins with ``0t'' or
``0x'' as described above.
The lsof user can control the switch from ``0t'' to ``0x'' with the -o o option. Consult
its description for more information.
If the -s option is specified, lsof always displays the file size (or nothing if no size
is available) and labels the column SIZE. The -o and -s options are mutually exclusive;
they can't both be specified.
If the -H option is specified, lsof displays file size in human readable form.
For files that don't have a fixed size - e.g., don't reside on a disk device - lsof will
display appropriate information about the current size or position of the file if it is
available in the kernel structures that define the file.
NLINK contains the file link count when +L has been specified;
NODE is the node number of a local file;
or the inode number of an NFS file in the server host;
or the Internet protocol type - e.g, ``TCP'';
or ``STR'' for a stream;
or ``CCITT'' for an HP-UX x.25 socket;
or the IRQ or inode number of a Linux AX.25 socket device.
NAME is the name of the mount point and file system on which the file resides;
or the name of a file specified in the names option (after any symbolic links have been
resolved);
or the name of a character special or block special device;
or the local and remote Internet addresses of a network file; the local host name or IP
number is followed by a colon (':'), the port, ``->'', and the two-part remote address; IP
addresses may be reported as numbers or names, depending on the +|-M, -n, and -P options;
colon-separated IPv6 numbers are enclosed in square brackets; IPv4 INADDR_ANY and IPv6
IN6_IS_ADDR_UNSPECIFIED addresses, and zero port numbers are represented by an asterisk
('*'); a UDP destination address may be followed by the amount of time elapsed since the
last packet was sent to the destination; TCP, UDP and UDPLITE remote addresses may be folā
lowed by TCP/TPI information in parentheses - state (e.g., ``(ESTABLISHED)'', ``(Unā
bound)''), queue sizes, and window sizes (not all dialects) - in a fashion similar to what
netstat(1) reports; see the -T option description or the description of the TCP/TPI field
in OUTPUT FOR OTHER PROGRAMS for more information on state, queue size, and window size;
or the address or name of a UNIX domain socket, possibly including a stream clone device
name, a file system object's path name, local and foreign kernel addresses, socket pair
information, and a bound vnode address;
or the local and remote mount point names of an NFS file;
or ``STR'', followed by the stream name;
or a stream character device name, followed by ``->'' and the stream name or a list of
stream module names, separated by ``->'';
or ``STR:'' followed by the SCO OpenServer stream device and module names, separated by
``->'';
or system directory name, `` -- '', and as many components of the path name as lsof can
find in the kernel's name cache for selected dialects (See the KERNEL NAME CACHE section
for more information.);
or ``PIPE->'', followed by a Solaris kernel pipe destination address;
or ``COMMON:'', followed by the vnode device information structure's device name, for a
Solaris common vnode;
or the address family, followed by a slash (`/'), followed by fourteen comma-separated
bytes of a non-Internet raw socket address;
or the HP-UX x.25 local address, followed by the virtual connection number (if any), folā
lowed by the remote address (if any);
or ``(dead)'' for disassociated Tru64 UNIX files - typically terminal files that have been
flagged with the TIOCNOTTY ioctl and closed by daemons;
or ``rd='' and ``wr='' for the values of the read and write offsets of a
FIFO;
or ``clone n:/dev/event'' for SCO OpenServer file clones of the /dev/event device, where n
is the minor device number of the file;
or ``(socketpair: n)'' for a Solaris 2.6, 8, 9 or 10 UNIX domain socket, created by the
socketpair(3N) network function;
or ``no PCB'' for socket files that do not have a protocol block associated with them, opā
tionally followed by ``, CANTSENDMORE'' if sending on the socket has been disabled, or ``,
CANTRCVMORE'' if receiving on the socket has been disabled (e.g., by the shutdown(2) funcā
tion);
or the local and remote addresses of a Linux IPX socket file in the form
:[:], followed in parentheses by the transmit and receive queue sizes,
and the connection state;
or ``dgram'' or ``stream'' for the type UnixWare 7.1.1 and above in-kernel UNIX domain
sockets, followed by a colon (':') and the local path name when available, followed by
``->'' and the remote path name or kernel socket address in hexadecimal when available;
or the association value, association index, endpoint value, local address, local port,
remote address and remote port for Linux SCTP sockets;
or ``protocol: '' followed by the Linux socket's protocol attribute.
For dialects that support a ``namefs'' file system, allowing one file to be attached to another with
fattach(3C), lsof will add ``(FA:)'' to the NAME column.
and are hexadecimal vnode addresses. will be ``<-'' if has been
fattach'ed to this vnode whose address is ; and ``->'' if , the vnode address of
this vnode, has been fattach'ed to . may be omitted if it already appears in
the DEVICE column.
Lsof may add two parenthetical notes to the NAME column for open Solaris 10 files: ``(?)'' if lsof
considers the path name of questionable accuracy; and ``(deleted)'' if the -X option has been speciā
fied and lsof detects the open file's path name has been deleted. Consult the lsof FAQ (The FAQ secā
tion gives its location.) for more information on these NAME column additions.
LOCKS
Lsof can't adequately report the wide variety of UNIX dialect file locks in a single character. What
it reports in a single character is a compromise between the information it finds in the kernel and
the limitations of the reporting format.
Moreover, when a process holds several byte level locks on a file, lsof only reports the status of
the first lock it encounters. If it is a byte level lock, then the lock character will be reported
in lower case - i.e., `r', `w', or `x' - rather than the upper case equivalent reported for a full
file lock.
Generally lsof can only report on locks held by local processes on local files. When a local process
sets a lock on a remotely mounted (e.g., NFS) file, the remote server host usually records the lock
state. One exception is Solaris - at some patch levels of 2.3, and in all versions above 2.4, the
Solaris kernel records information on remote locks in local structures.
Lsof has trouble reporting locks for some UNIX dialects. Consult the BUGS section of this manual
page or the lsof FAQ (The FAQ section gives its location.) for more information.
OUTPUT FOR OTHER PROGRAMS
When the -F option is specified, lsof produces output that is suitable for processing by another proā
gram - e.g, an awk or Perl script, or a C program.
Each unit of information is output in a field that is identified with a leading character and termiā
nated by a NL (012) (or a NUL (000) if the 0 (zero) field identifier character is specified.) The
data of the field follows immediately after the field identification character and extends to the
field terminator.
It is possible to think of field output as process and file sets. A process set begins with a field
whose identifier is `p' (for process IDentifier (PID)). It extends to the beginning of the next PID
field or the beginning of the first file set of the process, whichever comes first. Included in the
process set are fields that identify the command, the process group IDentification (PGID) number, the
task (thread) ID (TID), and the user ID (UID) number or login name.
A file set begins with a field whose identifier is `f' (for file descriptor). It is followed by
lines that describe the file's access mode, lock state, type, device, size, offset, inode, protocol,
name and stream module names. It extends to the beginning of the next file or process set, whichever
comes first.
When the NUL (000) field terminator has been selected with the 0 (zero) field identifier character,
lsof ends each process and file set with a NL (012) character.
Lsof always produces one field, the PID (`p') field. In repeat mode, the marker (`m') is also proā
duced. All other fields may be declared optionally in the field identifier character list that folā
lows the -F option. When a field selection character identifies an item lsof does not normally list
- e.g., PPID, selected with -R - specification of the field character - e.g., ``-FR'' - also selects
the listing of the item.
Lsof version from 4.88 to 4.93.2 always produced one more field, the file descriptor (`f') field.
However, lsof in this version doesn't produce it. This change is for supporting the use case that a
user needs only the PID field, and doesn't need the file descriptor field. Specify `f' explicitly if
you need the field.
It is entirely possible to select a set of fields that cannot easily be parsed - e.g., if the field
descriptor field is not selected, it may be difficult to identify file sets. To help you avoid this
difficulty, lsof supports the -F option; it selects the output of all fields with NL terminators (the
-F0 option pair selects the output of all fields with NUL terminators). For compatibility reasons
neither -F nor -F0 select the raw device field.
These are the fields that lsof will produce. The single character listed first is the field identiā
fier.
a file access mode
c process command name (all characters from proc or
user structure)
C file structure share count
d file's device character code
D file's major/minor device number (0x)
f file descriptor
F file structure address (0x)
G file flaGs (0x; names if +fg follows)
g process group ID
i file's inode number
K tasK ID
k link count
l file's lock status
L process login name
m marker between repeated output (always selected in repeat mode)
M the task comMand name
n file name, comment, Internet address
N node identifier (ox
o file's offset (0t or 0x, see -o o)
p process ID (always selected)
P protocol name
r raw device number (0x)
R parent process ID
s file's size (decimal)
S file's stream identification
t file's type
T TCP/TPI information, identified by prefixes (the
`=' is part of the prefix):
QR=
QS=
SO= (not all dialects)
SS= (not all dialects)
ST=
TF= (not all dialects)
WR= (not all dialects)
WW= (not all dialects)
(TCP/TPI information isn't reported for all supported
UNIX dialects. The -h or -? help output for the
-T option will show what TCP/TPI reporting can be
requested.)
u process user ID
z Solaris 10 and higher zone name
Z SELinux security context (inhibited when SELinux is disabled)
0 use NUL field terminator character in place of NL
1-9 dialect-specific field identifiers (The output
of -F? identifies the information to be found
in dialect-specific fields.)
You can get on-line help information on these characters and their descriptions by specifying the -F?
option pair. (Escape the `?' character as your shell requires.) Additional information on field
content can be found in the OUTPUT section.
As an example, ``-F pcfn'' will select the process ID (`p'), command name (`c'), file descriptor
(`f') and file name (`n') fields with an NL field terminator character; ``-F pcfn0'' selects the same
output with a NUL (000) field terminator character.
Lsof doesn't produce all fields for every process or file set, only those that are available. Some
fields are mutually exclusive: file device characters and file major/minor device numbers; file inode
number and protocol name; file name and stream identification; file size and offset. One or the
other member of these mutually exclusive sets will appear in field output, but not both.
Normally lsof ends each field with a NL (012) character. The 0 (zero) field identifier character may
be specified to change the field terminator character to a NUL (000). A NUL terminator may be easier
to process with xargs (1), for example, or with programs whose quoting mechanisms may not easily cope
with the range of characters in the field output. When the NUL field terminator is in use, lsof ends
each process and file set with a NL (012).
Three aids to producing programs that can process lsof field output are included in the lsof distribā
ution. The first is a C header file, lsof_fields.h, that contains symbols for the field identificaā
tion characters, indexes for storing them in a table, and explanation strings that may be compiled
into programs. Lsof uses this header file.
The second aid is a set of sample scripts that process field output, written in awk, Perl 4, and Perl
5. They're located in the scripts subdirectory of the lsof distribution.
The third aid is the C library used for the lsof test suite. The test suite is written in C and uses
field output to validate the correct operation of lsof. The library can be found in the
tests/LTlib.c file of the lsof distribution. The library uses the first aid, the lsof_fields.h
header file.
BLOCKS AND TIMEOUTS
Lsof can be blocked by some kernel functions that it uses - lstat(2), readlink(2), and stat(2).
These functions are stalled in the kernel, for example, when the hosts where mounted NFS file systems
reside become inaccessible.
Lsof attempts to break these blocks with timers and child processes, but the techniques are not
wholly reliable. When lsof does manage to break a block, it will report the break with an error mesā
sage. The messages may be suppressed with the -t and -w options.
The default timeout value may be displayed with the -h or -? option, and it may be changed with the
-S [t] option. The minimum for t is two seconds, but you should avoid small values, since slow sysā
tem responsiveness can cause short timeouts to expire unexpectedly and perhaps stop lsof before it
can produce any output.
When lsof has to break a block during its access of mounted file system information, it normally conā
tinues, although with less information available to display about open files.
Lsof can also be directed to avoid the protection of timers and child processes when using the kernel
functions that might block by specifying the -O option. While this will allow lsof to start up with
less overhead, it exposes lsof completely to the kernel situations that might block it. Use this opā
tion cautiously.
AVOIDING KERNEL BLOCKS
You can use the -b option to tell lsof to avoid using kernel functions that would block. Some cauā
tions apply.
First, using this option usually requires that your system supply alternate device numbers in place
of the device numbers that lsof would normally obtain with the lstat(2) and stat(2) kernel functions.
See the ALTERNATE DEVICE NUMBERS section for more information on alternate device numbers.
Second, you can't specify names for lsof to locate unless they're file system names. This is because
lsof needs to know the device and inode numbers of files listed with names in the lsof options, and
the -b option prevents lsof from obtaining them. Moreover, since lsof only has device numbers for
the file systems that have alternates, its ability to locate files on file systems depends completely
on the availability and accuracy of the alternates. If no alternates are available, or if they're
incorrect, lsof won't be able to locate files on the named file systems.
Third, if the names of your file system directories that lsof obtains from your system's mount table
are symbolic links, lsof won't be able to resolve the links. This is because the -b option causes
lsof to avoid the kernel readlink(2) function it uses to resolve symbolic links.
Finally, using the -b option causes lsof to issue warning messages when it needs to use the kernel
functions that the -b option directs it to avoid. You can suppress these messages by specifying the
-w option, but if you do, you won't see the alternate device numbers reported in the warning mesā
sages.
ALTERNATE DEVICE NUMBERS
On some dialects, when lsof has to break a block because it can't get information about a mounted
file system via the lstat(2) and stat(2) kernel functions, or because you specified the -b option,
lsof can obtain some of the information it needs - the device number and possibly the file system
type - from the system mount table. When that is possible, lsof will report the device number it obā
tained. (You can suppress the report by specifying the -w option.)
You can assist this process if your mount table is supported with an /etc/mtab or /etc/mnttab file
that contains an options field by adding a ``dev=xxxx'' field for mount points that do not have one
in their options strings. Note: you must be able to edit the file - i.e., some mount tables like reā
cent Solaris /etc/mnttab or Linux /proc/mounts are read-only and can't be modified.
You may also be able to supply device numbers using the +m and +m m options, provided they are supā
ported by your dialect. Check the output of lsof's -h or -? options to see if the +m and +m m opā
tions are available.
The ``xxxx'' portion of the field is the hexadecimal value of the file system's device number. (Conā
sult the st_dev field of the output of the lstat(2) and stat(2) functions for the appropriate values
for your file systems.) Here's an example from a Sun Solaris 2.6 /etc/mnttab for a file system reā
motely mounted via NFS:
nfs ignore,noquota,dev=2a40001
There's an advantage to having ``dev=xxxx'' entries in your mount table file, especially for file
systems that are mounted from remote NFS servers. When a remote server crashes and you want to idenā
tify its users by running lsof on one of its clients, lsof probably won't be able to get output from
the lstat(2) and stat(2) functions for the file system. If it can obtain the file system's device
number from the mount table, it will be able to display the files open on the crashed NFS server.
Some dialects that do not use an ASCII /etc/mtab or /etc/mnttab file for the mount table may still
provide an alternative device number in their internal mount tables. This includes AIX, Apple Darā
win, FreeBSD, NetBSD, OpenBSD, and Tru64 UNIX. Lsof knows how to obtain the alternative device numā
ber for these dialects and uses it when its attempt to lstat(2) or stat(2) the file system is
blocked.
If you're not sure your dialect supplies alternate device numbers for file systems from its mount taā
ble, use this lsof incantation to see if it reports any alternate device numbers:
lsof -b
Look for standard error file warning messages that begin ``assuming "dev=xxxx" from ...''.
KERNEL NAME CACHE
Lsof is able to examine the kernel's name cache or use other kernel facilities (e.g., the ADVFS 4.x
tag_to_path() function under Tru64 UNIX) on some dialects for most file system types, excluding AFS,
and extract recently used path name components from it. (AFS file system path lookups don't use the
kernel's name cache; some Solaris VxFS file system operations apparently don't use it, either.)
Lsof reports the complete paths it finds in the NAME column. If lsof can't report all components in
a path, it reports in the NAME column the file system name, followed by a space, two `-' characters,
another space, and the name components it has located, separated by the `/' character.
When lsof is run in repeat mode - i.e., with the -r option specified - the extent to which it can reā
port path name components for the same file may vary from cycle to cycle. That's because other runā
ning processes can cause the kernel to remove entries from its name cache and replace them with othā
ers.
Lsof's use of the kernel name cache to identify the paths of files can lead it to report incorrect
components under some circumstances. This can happen when the kernel name cache uses device and node
number as a key (e.g., SCO OpenServer) and a key on a rapidly changing file system is reused. If the
UNIX dialect's kernel doesn't purge the name cache entry for a file when it is unlinked, lsof may
find a reference to the wrong entry in the cache. The lsof FAQ (The FAQ section gives its location.)
has more information on this situation.
Lsof can report path name components for these dialects:
FreeBSD
HP-UX
Linux
NetBSD
SCO OpenServer
SCO|Caldera UnixWare
Solaris
Tru64 UNIX
Lsof can't report path name components for these dialects:
AIX
OpenBSD
If you want to know why lsof can't report path name components for some dialects, see the lsof FAQ
(The FAQ section gives its location.)
DEVICE CACHE FILE
Examining all members of the /dev (or /devices) node tree with stat(2) functions can be time consumā
ing. What's more, the information that lsof needs - device number, inode number, and path - rarely
changes.
Consequently, lsof normally maintains an ASCII text file of cached /dev (or /devices) information
(exception: the /proc-based Linux lsof where it's not needed.) The local system administrator who
builds lsof can control the way the device cache file path is formed, selecting from these options:
Path from the -D option;
Path from an environment variable;
System-wide path;
Personal path (the default);
Personal path, modified by an environment variable.
Consult the output of the -h, -D? , or -? help options for the current state of device cache supā
port. The help output lists the default read-mode device cache file path that is in effect for the
current invocation of lsof. The -D? option output lists the read-only and write device cache file
paths, the names of any applicable environment variables, and the personal device cache path format.
Lsof can detect that the current device cache file has been accidentally or maliciously modified by
integrity checks, including the computation and verification of a sixteen bit Cyclic Redundancy Check
(CRC) sum on the file's contents. When lsof senses something wrong with the file, it issues a warnā
ing and attempts to remove the current cache file and create a new copy, but only to a path that the
process can legitimately write.
The path from which a lsof process may attempt to read a device cache file may not be the same as the
path to which it can legitimately write. Thus when lsof senses that it needs to update the device
cache file, it may choose a different path for writing it from the path from which it read an incorā
rect or outdated version.
If available, the -Dr option will inhibit the writing of a new device cache file. (It's always
available when specified without a path name argument.)
When a new device is added to the system, the device cache file may need to be recreated. Since lsof
compares the mtime of the device cache file with the mtime and ctime of the /dev (or /devices) direcā
tory, it usually detects that a new device has been added; in that case lsof issues a warning message
and attempts to rebuild the device cache file.
Whenever lsof writes a device cache file, it sets its ownership to the real UID of the executing
process, and its permission modes to 0600, this restricting its reading and writing to the file's
owner.
LSOF PERMISSIONS THAT AFFECT DEVICE CACHE FILE ACCESS
Two permissions of the lsof executable affect its ability to access device cache files. The permisā
sions are set by the local system administrator when lsof is installed.
The first and rarer permission is setuid-root. It comes into effect when lsof is executed; its efā
fective UID is then root, while its real (i.e., that of the logged-on user) UID is not. The lsof
distribution recommends that versions for these dialects run setuid-root.
HP-UX 11.11 and 11.23
Linux
The second and more common permission is setgid. It comes into effect when the effective group IDenā
tification number (GID) of the lsof process is set to one that can access kernel memory devices -
e.g., ``kmem'', ``sys'', or ``system''.
An lsof process that has setgid permission usually surrenders the permission after it has accessed
the kernel memory devices. When it does that, lsof can allow more liberal device cache path formaā
tions. The lsof distribution recommends that versions for these dialects run setgid and be allowed
to surrender setgid permission.
AIX 5.[12] and 5.3-ML1
Apple Darwin 7.x Power Macintosh systems
FreeBSD 4.x, 4.1x, 5.x and [6789].x for x86-based systems
FreeBSD 5.x, [6789].x and 1[012].8for Alpha, AMD64 and Sparc64
based systems
HP-UX 11.00
NetBSD 1.[456], 2.x and 3.x for Alpha, x86, and SPARC-based
systems
OpenBSD 2.[89] and 3.[0-9] for x86-based systems
SCO OpenServer Release 5.0.6 for x86-based systems
SCO|Caldera UnixWare 7.1.4 for x86-based systems
Solaris 2.6, 8, 9 and 10
Tru64 UNIX 5.1
(Note: lsof for AIX 5L and above needs setuid-root permission if its -X option is used.)
Lsof for these dialects does not support a device cache, so the permissions given to the executable
don't apply to the device cache file.
Linux
DEVICE CACHE FILE PATH FROM THE -D OPTION
The -D option provides limited means for specifying the device cache file path. Its ? function will
report the read-only and write device cache file paths that lsof will use.
When the -D b, r, and u functions are available, you can use them to request that the cache file be
built in a specific location (b[path]); read but not rebuilt (r[path]); or read and rebuilt
(u[path]). The b, r, and u functions are restricted under some conditions. They are restricted when
the lsof process is setuid-root. The path specified with the r function is always read-only, even
when it is available.
The b, r, and u functions are also restricted when the lsof process runs setgid and lsof doesn't surā
render the setgid permission. (See the LSOF PERMISSIONS THAT AFFECT DEVICE CACHE FILE ACCESS section
for a list of implementations that normally don't surrender their setgid permission.)
A further -D function, i (for ignore), is always available.
When available, the b function tells lsof to read device information from the kernel with the stat(2)
function and build a device cache file at the indicated path.
When available, the r function tells lsof to read the device cache file, but not update it. When a
path argument accompanies -Dr, it names the device cache file path. The r function is always availā
able when it is specified without a path name argument. If lsof is not running setuid-root and surā
renders its setgid permission, a path name argument may accompany the r function.
When available, the u function tells lsof to attempt to read and use the device cache file. If it
can't read the file, or if it finds the contents of the file incorrect or outdated, it will read inā
formation from the kernel, and attempt to write an updated version of the device cache file, but only
to a path it considers legitimate for the lsof process effective and real UIDs.
DEVICE CACHE PATH FROM AN ENVIRONMENT VARIABLE
Lsof's second choice for the device cache file is the contents of the LSOFDEVCACHE environment variā
able. It avoids this choice if the lsof process is setuid-root, or the real UID of the process is
root.
A further restriction applies to a device cache file path taken from the LSOFDEVCACHE environment
variable: lsof will not write a device cache file to the path if the lsof process doesn't surrender
its setgid permission. (See the LSOF PERMISSIONS THAT AFFECT DEVICE CACHE FILE ACCESS section for
information on implementations that don't surrender their setgid permission.)
The local system administrator can disable the use of the LSOFDEVCACHE environment variable or change
its name when building lsof. Consult the output of -D? for the environment variable's name.
SYSTEM-WIDE DEVICE CACHE PATH
The local system administrator may choose to have a system-wide device cache file when building lsof.
That file will generally be constructed by a special system administration procedure when the system
is booted or when the contents of /dev or /devices) changes. If defined, it is lsof's third device
cache file path choice.
You can tell that a system-wide device cache file is in effect for your local installation by examinā
ing the lsof help option output - i.e., the output from the -h or -? option.
Lsof will never write to the system-wide device cache file path by default. It must be explicitly
named with a -D function in a root-owned procedure. Once the file has been written, the procedure
must change its permission modes to 0644 (owner-read and owner-write, group-read, and other-read).
PERSONAL DEVICE CACHE PATH (DEFAULT)
The default device cache file path of the lsof distribution is one recorded in the home directory of
the real UID that executes lsof. Added to the home directory is a second path component of the form
.lsof_hostname.
This is lsof's fourth device cache file path choice, and is usually the default. If a system-wide
device cache file path was defined when lsof was built, this fourth choice will be applied when lsof
can't find the system-wide device cache file. This is the only time lsof uses two paths when reading
the device cache file.
The hostname part of the second component is the base name of the executing host, as returned by
gethostname(2). The base name is defined to be the characters preceding the first `.' in the gethā
ostname(2) output, or all the gethostname(2) output if it contains no `.'.
The device cache file belongs to the user ID and is readable and writable by the user ID alone -
i.e., its modes are 0600. Each distinct real user ID on a given host that executes lsof has a disā
tinct device cache file. The hostname part of the path distinguishes device cache files in an
NFS-mounted home directory into which device cache files are written from several different hosts.
The personal device cache file path formed by this method represents a device cache file that lsof
will attempt to read, and will attempt to write should it not exist or should its contents be incorā
rect or outdated.
The -Dr option without a path name argument will inhibit the writing of a new device cache file.
The -D? option will list the format specification for constructing the personal device cache file.
The conversions used in the format specification are described in the 00DCACHE file of the lsof disā
tribution.
MODIFIED PERSONAL DEVICE CACHE PATH
If this option is defined by the local system administrator when lsof is built, the LSOFPERSDCPATH
environment variable contents may be used to add a component of the personal device cache file path.
The LSOFPERSDCPATH variable contents are inserted in the path at the place marked by the local system
administrator with the ``%p'' conversion in the HASPERSDC format specification of the dialect's maā
chine.h header file. (It's placed right after the home directory in the default lsof distribution.)
Thus, for example, if LSOFPERSDCPATH contains ``LSOF'', the home directory is ``/Homes/abe'', the
host name is ``lsof.itap.purdue.edu'', and the HASPERSDC format is the default (``%h/%p.lsof_%L''),
the modified personal device cache file path is:
/Homes/abe/LSOF/.lsof_vic
The LSOFPERSDCPATH environment variable is ignored when the lsof process is setuid-root or when the
real UID of the process is root.
Lsof will not write to a modified personal device cache file path if the lsof process doesn't surrenā
der setgid permission. (See the LSOF PERMISSIONS THAT AFFECT DEVICE CACHE FILE ACCESS section for a
list of implementations that normally don't surrender their setgid permission.)
If, for example, you want to create a sub-directory of personal device cache file paths by using the
LSOFPERSDCPATH environment variable to name it, and lsof doesn't surrender its setgid permission, you
will have to allow lsof to create device cache files at the standard personal path and move them to
your subdirectory with shell commands.
The local system administrator may: disable this option when lsof is built; change the name of the
environment variable from LSOFPERSDCPATH to something else; change the HASPERSDC format to include
the personal path component in another place; or exclude the personal path component entirely. Conā
sult the output of the -D? option for the environment variable's name and the HASPERSDC format specā
ification.
DIAGNOSTICS
Errors are identified with messages on the standard error file.
Lsof returns a one (1) if any error was detected, including the failure to locate command names, file
names, Internet addresses or files, login names, NFS files, PIDs, PGIDs, or UIDs it was asked to
list. If the -V option is specified, lsof will indicate the search items it failed to list. If the
-Q option is specified, lsof will ignore any search item failures and only return an error if someā
thing unusual and unrecoverable happened.
It returns a zero (0) if no errors were detected and if either the -Q option was specified or it was
able to list some information about all the specified search arguments.
When lsof cannot open access to /dev (or /devices) or one of its subdirectories, or get information
on a file in them with stat(2), it issues a warning message and continues. That lsof will issue
warning messages about inaccessible files in /dev (or /devices) is indicated in its help output - reā
quested with the -h or >B -? options - with the message:
Inaccessible /dev warnings are enabled.
The warning message may be suppressed with the -w option. It may also have been suppressed by the
system administrator when lsof was compiled by the setting of the WARNDEVACCESS definition. In this
case, the output from the help options will include the message:
Inaccessible /dev warnings are disabled.
Inaccessible device warning messages usually disappear after lsof has created a working device cache
file.
EXAMPLES
For a more extensive set of examples, documented more fully, see the 00QUICKSTART file of the lsof
distribution.
To list all open files, use:
lsof
To list all open Internet, x.25 (HP-UX), and UNIX domain files, use:
lsof -i -U
To list all open IPv4 network files in use by the process whose PID is 1234, use:
lsof -i 4 -a -p 1234
If it's okay for PID 1234 to not exist, or for PID 1234 to not have any open IPv4 network files, add
-Q :
lsof -Q -i 4 -a -p 1234
Presuming the UNIX dialect supports IPv6, to list only open IPv6 network files, use:
lsof -i 6
To list all files using any protocol on ports 513, 514, or 515 of host wonderland.cc.purdue.edu, use:
lsof -i @wonderland.cc.purdue.edu:513-515
To list all files using any protocol on any port of mace.cc.purdue.edu (cc.purdue.edu is the default
domain), use:
lsof -i @mace
To list all open files for login name ``abe'', or user ID 1234, or process 456, or process 123, or
process 789, use:
lsof -p 456,123,789 -u 1234,abe
To list all open files on device /dev/hd4, use:
lsof /dev/hd4
To find the process that has /u/abe/foo open without worrying if there are none, use:
lsof -Q /u/abe/foo
To take action only if a process has /u/abe/foo open, use:
lsof /u/abe/foo echo "still in use"
To send a SIGHUP to the processes that have /u/abe/bar open, use:
kill -HUP `lsof -t /u/abe/bar`
To find any open file, including an open UNIX domain socket file, with the name /dev/log, use:
lsof /dev/log
To find processes with open files on the NFS file system named /nfs/mount/point whose server is inacā
cessible, and presuming your mount table supplies the device number for /nfs/mount/point, use:
lsof -b /nfs/mount/point
To do the preceding search with warning messages suppressed, use:
lsof -bw /nfs/mount/point
To ignore the device cache file, use:
lsof -Di
To obtain PID and command name field output for each process, file descriptor, file device number,
and file inode number for each file of each process, use:
lsof -FpcfDi
To list the files at descriptors 1 and 3 of every process running the lsof command for login ID
``abe'' every 10 seconds, use:
lsof -c lsof -a -d 1 -d 3 -u abe -r10
To list the current working directory of processes running a command that is exactly four characters
long and has an 'o' or 'O' in character three, use this regular expression form of the -c c option:
lsof -c /^..o.$/i -a -d cwd
To find an IP version 4 socket file by its associated numeric dot-form address, use:
lsof -i@128.210.15.17
To find an IP version 6 socket file (when the UNIX dialect supports IPv6) by its associated numeric
colon-form address, use:
lsof -i@[0:1:2:3:4:5:6:7]
To find an IP version 6 socket file (when the UNIX dialect supports IPv6) by an associated numeric
colon-form address that has a run of zeroes in it - e.g., the loop-back address - use:
lsof -i@[::1]
To obtain a repeat mode marker line that contains the current time, use:
lsof -rm====%T====
To add spaces to the previous marker line, use:
lsof -r "m==== %T ===="
BUGS
Since lsof reads kernel memory in its search for open files, rapid changes in kernel memory may proā
duce unpredictable results.
When a file has multiple record locks, the lock status character (following the file descriptor) is
derived from a test of the first lock structure, not from any combination of the individual record
locks that might be described by multiple lock structures.
Lsof can't search for files with restrictive access permissions by name unless it is installed with
root set-UID permission. Otherwise it is limited to searching for files to which its user or its
set-GID group (if any) has access permission.
The display of the destination address of a raw socket (e.g., for ping) depends on the UNIX operating
system. Some dialects store the destination address in the raw socket's protocol control block, some
do not.
Lsof can't always represent Solaris device numbers in the same way that ls(1) does. For example, the
major and minor device numbers that the lstat(2) and stat(2) functions report for the directory on
which CD-ROM files are mounted (typically /cdrom) are not the same as the ones that it reports for
the device on which CD-ROM files are mounted (typically /dev/sr0). (Lsof reports the directory numā
bers.)
The support for /proc file systems is available only for BSD and Tru64 UNIX dialects, Linux, and diā
alects derived from SYSV R4 - e.g., FreeBSD, NetBSD, OpenBSD, Solaris, UnixWare.
Some /proc file items - device number, inode number, and file size - are unavailable in some diā
alects. Searching for files in a /proc file system may require that the full path name be specified.
No text (txt) file descriptors are displayed for Linux processes. All entries for files other than
the current working directory, the root directory, and numerical file descriptors are labeled mem deā
scriptors.
Lsof can't search for Tru64 UNIX named pipes by name, because their kernel implementation of lstat(2)
returns an improper device number for a named pipe.
Lsof can't report fully or correctly on HP-UX 9.01, 10.20, and 11.00 locks because of insufficient
access to kernel data or errors in the kernel data. See the lsof FAQ (The FAQ section gives its loā
cation.) for details.
The AIX SMT file type is a fabrication. It's made up for file structures whose type (15) isn't deā
fined in the AIX /usr/include/sys/file.h header file. One way to create such file structures is to
run X clients with the DISPLAY variable set to ``:0.0''.
The +|-f[cfn] option is not supported under /proc-based Linux lsof, because it doesn't read kernel
structures from kernel memory.
ENVIRONMENT
Lsof may access these environment variables.
LANG defines a language locale. See setlocale(3) for the names of other variables that
can be used in place of LANG - e.g., LC_ALL, LC_TYPE, etc.
LSOFDEVCACHE defines the path to a device cache file. See the DEVICE CACHE PATH FROM AN ENVIā
RONMENT VARIABLE section for more information.
LSOFPERSDCPATH defines the middle component of a modified personal device cache file path. See
the MODIFIED PERSONAL DEVICE CACHE PATH section for more information.
FAQ
Frequently-asked questions and their answers (an FAQ) are available in the 00FAQ file of the lsof
distribution.
That latest version of the file is found at:
https://github.com/lsof-org/lsof/blob/master/00FAQ
FILES
/dev/kmem kernel virtual memory device
/dev/mem physical memory device
/dev/swap system paging device
.lsof_hostname lsof's device cache file (The suffix, hostname, is the first component of the
host's name returned by gethostname(2).)
AUTHORS
Lsof was written by Victor A.Abell of Purdue University. Since version 4.93.0, the
lsof-org team at GitHub maintains lsof. Many others have contributed to lsof. They're listed in the
00CREDITS file of the lsof distribution.
DISTRIBUTION
The latest distribution of lsof is available at
https://github.com/lsof-org/lsof/releases
SEE ALSO
Not all the following manual pages may exist in every UNIX dialect to which lsof has been ported.
access(2), awk(1), crash(1), fattach(3C), ff(1), fstat(8), fuser(1), gethostname(2), isprint(3),
kill(1), localtime(3), lstat(2), modload(8), mount(8), netstat(1), ofiles(8L), open(2), perl(1),
ps(1), readlink(2), setlocale(3), stat(2), strftime(3), time(2), uname(1).
Revision-4.99.4 LSOF(8)