Manual: gmake

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 Stall‐
       man 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 language 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-modi‐
       fication	 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 promi‐
       nently  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 options are speci‐
	    fied, 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 details 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  rebuild
	    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  option,  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 depend 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 circumstances).

       -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 anything 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 together 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 output 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 commands.	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	war‐
	    ranty.

       -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 reverse 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 hap‐
	    pen 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	 in‐
       stalled 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.

COPYRIGHT
       Copyright © 1992-1993, 1996-2023 Free Software Foundation, Inc.	This file is part of GNU Make.

       GNU Make is free software; you can redistribute it and/or modify it under the terms of the GNU General 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	war‐
       ranty 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)