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 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 the states
       the 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 target
       names, where name 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 options 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 a for all debugging output (same as using
            -d), b for basic debugging, v for more verbose basic debugging, i
            for showing implicit rules, j for details on invocation of
            commands, and m for debugging while remaking makefiles.  Use n 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.

       -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 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.

       -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.

COPYRIGHT
       Copyright © 1992-1993, 1996-2020 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 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 http://www.gnu.org/licenses/.



GNU                            28 February 2016                        MAKE(1)