STANNIX Solutions for the Real World

Services About Contact Community

Manual: make

MAKE(1) User Commands MAKE(1)

NAME
make - GNU Make utility to maintain groups of programs

SYNOPSIS
make [OPTION]... [TARGET]...

DESCRIPTION
The make utility will determine automatically which pieces of a large program need to be recompiled,
and issue the commands to recompile them. The manual describes the GNU implementation of make, which
was written by Richard Stallman and Roland McGrath, and is currently maintained by Paul Smith. Our
examples show C programs, since they are very common, but you can use make with any programming lan‐
guage whose compiler can be run with a shell command. In fact, make is not limited to programs. You
can use it to describe any task where some files must be updated automatically from others whenever
the others change.

To prepare to use make, you must write a file called the makefile that describes the relationships
among files in your program, and provides commands for updating each file. In a program, typically
the executable file is updated from object files, which are in turn made by compiling source files.

Once a suitable makefile exists, each time you change some source files, this simple shell command:

make

suffices to perform all necessary recompilations. The make program uses the makefile description and
the last-modification times of the files to decide which of the files need to be updated. For each
of those files, it issues the commands recorded in the makefile.

make executes commands in the makefile to update one or more targets, where target is typically a
program. If no -f option is present, make will look for the makefiles GNUmakefile, makefile, and
Makefile, in that order.

Normally you should call your makefile either makefile or Makefile. (We recommend Makefile because
it appears prominently near the beginning of a directory listing, right near other important files
such as README.) The first name checked, GNUmakefile, is not recommended for most makefiles. You
should use this name if you have a makefile that is specific to GNU Make, and will not be understood
by other versions of make. If makefile is '-', the standard input is read.

make updates a target if it depends on prerequisite files that have been modified since the target
was last modified, or if the target does not exist.

OPTIONS
-b, -m
These options are ignored for compatibility with other versions of make.

-B, --always-make
Unconditionally make all targets.

-C dir, --directory=dir
Change to directory dir before reading the makefiles or doing anything else. If multiple -C op‐
tions are specified, each is interpreted relative to the previous one: -C / -C etc is equivalent
to -C /etc. This is typically used with recursive invocations of make.

-d Print debugging information in addition to normal processing. The debugging information says
which files are being considered for remaking, which file-times are being compared and with what
results, which files actually need to be remade, which implicit rules are considered and which
are applied---everything interesting about how make decides what to do.

--debug[=FLAGS]
Print debugging information in addition to normal processing. If the FLAGS are omitted, then
the behavior is the same as if -d was specified. FLAGS may be any or all of the following
names, comma- or space-separated. Only the first character is significant: the rest may be
omitted: all for all debugging output (same as using -d), basic for basic debugging, verbose for
more verbose basic debugging, implicit for showing implicit rule search operations, jobs for de‐
tails on invocation of commands, makefile for debugging while remaking makefiles, print shows
all recipes that are run even if they are silent, and why shows the reason make decided to re‐
build each target. Use none to disable all previous debugging flags.

-e, --environment-overrides
Give variables taken from the environment precedence over variables from makefiles.

-E string, --eval string
Interpret string using the eval function, before parsing any makefiles.

-f file, --file=file, --makefile=FILE
Use file as a makefile.

-i, --ignore-errors
Ignore all errors in commands executed to remake files.

-I dir, --include-dir=dir
Specifies a directory dir to search for included makefiles. If several -I options are used to
specify several directories, the directories are searched in the order specified. Unlike the
arguments to other flags of make, directories given with -I flags may come directly after the
flag: -Idir is allowed, as well as -I dir. This syntax is allowed for compatibility with the C
preprocessor's -I flag.

-j [jobs], --jobs[=jobs]
Specifies the number of jobs (commands) to run simultaneously. If there is more than one -j op‐
tion, the last one is effective. If the -j option is given without an argument, make will not
limit the number of jobs that can run simultaneously.

--jobserver-style=style
The style of jobserver to use. The style may be one of fifo, pipe, or sem (Windows only).

-k, --keep-going
Continue as much as possible after an error. While the target that failed, and those that de‐
pend on it, cannot be remade, the other dependencies of these targets can be processed all the
same.

-l [load], --load-average[=load]
Specifies that no new jobs (commands) should be started if there are others jobs running and the
load average is at least load (a floating-point number). With no argument, removes a previous
load limit.

-L, --check-symlink-times
Use the latest mtime between symlinks and target.

-n, --just-print, --dry-run, --recon
Print the commands that would be executed, but do not execute them (except in certain circum‐
stances).

-o file, --old-file=file, --assume-old=file
Do not remake the file file even if it is older than its dependencies, and do not remake any‐
thing on account of changes in file. Essentially the file is treated as very old and its rules
are ignored.

-O[type], --output-sync[=type]
When running multiple jobs in parallel with -j, ensure the output of each job is collected to‐
gether rather than interspersed with output from other jobs. If type is not specified or is
target the output from the entire recipe for each target is grouped together. If type is line
the output from each command line within a recipe is grouped together. If type is recurse out‐
put from an entire recursive make is grouped together. If type is none output synchronization
is disabled.

-p, --print-data-base
Print the data base (rules and variable values) that results from reading the makefiles; then
execute as usual or as otherwise specified. This also prints the version information given by
the -v switch (see below). To print the data base without trying to remake any files, use make
-p -f/dev/null.

-q, --question
``Question mode''. Do not run any commands, or print anything; just return an exit status that
is zero if the specified targets are already up to date, nonzero otherwise.

-r, --no-builtin-rules
Eliminate use of the built-in implicit rules. Also clear out the default list of suffixes for
suffix rules.

-R, --no-builtin-variables
Don't define any built-in variables.

-s, --silent, --quiet
Silent operation; do not print the commands as they are executed.

--no-silent
Cancel the effect of the -s option.

-S, --no-keep-going, --stop
Cancel the effect of the -k option.

-t, --touch
Touch files (mark them up to date without really changing them) instead of running their com‐
mands. This is used to pretend that the commands were done, in order to fool future invocations
of make.

--trace
Information about the disposition of each target is printed (why the target is being rebuilt and
what commands are run to rebuild it).

-v, --version
Print the version of the make program plus a copyright, a list of authors and a notice that
there is no warranty.

-w, --print-directory
Print a message containing the working directory before and after other processing. This may be
useful for tracking down errors from complicated nests of recursive make commands.

--no-print-directory
Turn off -w, even if it was turned on implicitly.

--shuffle[=MODE]
Enable shuffling of goal and prerequisite ordering. MODE is one of none to disable shuffle
mode, random to shuffle prerequisites in random order, reverse to consider prerequisites in re‐
verse order, or an integer which enables random mode with a specific seed value. If MODE
is omitted the default is random.

-W file, --what-if=file, --new-file=file, --assume-new=file
Pretend that the target file has just been modified. When used with the -n flag, this shows you
what would happen if you were to modify that file. Without -n, it is almost the same as running
a touch command on the given file before running make, except that the modification time is
changed only in the imagination of make.

--warn-undefined-variables
Warn when an undefined variable is referenced.

EXIT STATUS
GNU Make exits with a status of zero if all makefiles were successfully parsed and no targets that
were built failed. A status of one will be returned if the -q flag was used and make determines that
a target needs to be rebuilt. A status of two will be returned if any errors were encountered.

SEE ALSO
The full documentation for make is maintained as a Texinfo manual. If the info and make programs are
properly installed at your site, the command

info make

should give you access to the complete manual.

BUGS
See the chapter ``Problems and Bugs'' in The GNU Make Manual.

AUTHOR
This manual page contributed by Dennis Morse of Stanford University. Further updates contributed by
Mike Frysinger. It has been reworked by Roland McGrath. Maintained by Paul Smith.

GNU Make is free software; you can redistribute it and/or modify it under the terms of the GNU Gen‐
eral Public License as published by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.

GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not,
see https://www.gnu.org/licenses/.

GNU 26 May 2023 MAKE(1)

← Back to Index

Manual: make

Related Commands: