NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXIT STATUS | SEE ALSO | BUGS | AUTHOR | COPYRIGHT | COLOPHON

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.

       -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.

       -S, --no-keep-going, --stop
            Cancel the effect of the -k option.  This is never necessary
            except in a recursive make where -k might be inherited from the
            top-level make via MAKEFLAGS or if you set -k in MAKEFLAGS in
            your environment.

       -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, 1996-2016 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-4.2.tar.gz fetched from ⟨http://ftp.gnu.org/gnu/make/⟩
       on 2017-09-15.  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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