make(1) — Linux manual page

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MAKE(1)                       User Commands                      MAKE(1)

NAME         top

       make - GNU make utility to maintain groups of programs

SYNOPSIS         top

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

DESCRIPTION         top

       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         top

       -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         top

       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         top

       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         top

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

AUTHOR         top

       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         top

       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/ .

COLOPHON         top

       This page is part of the make (GNU make) project.  Information
       about the project can be found at 
       ⟨http://www.gnu.org/software/make/⟩.  If you have a bug report for
       this manual page, see ⟨http://www.gnu.org/software/make/⟩.  This
       page was obtained from the tarball make-4.3.tar.gz fetched from
       ⟨http://ftp.gnu.org/gnu/make/⟩ on 2021-04-01.  If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page,
       or you have corrections or improvements to the information in
       this COLOPHON (which is not part of the original manual page),
       send a mail to man-pages@man7.org

GNU                         28 February 2016                     MAKE(1)

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