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 MAKE(1)                             GNU                             MAKE(1)
 User Commands                                                 User Commands

                              28 February 2016



 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.




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 MAKE(1)                             GNU                             MAKE(1)
 User Commands                                                 User Commands

                              28 February 2016



      -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



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 MAKE(1)                             GNU                             MAKE(1)
 User Commands                                                 User Commands

                              28 February 2016



           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.




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 MAKE(1)                             GNU                             MAKE(1)
 User Commands                                                 User Commands

                              28 February 2016



      -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.




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 MAKE(1)                             GNU                             MAKE(1)
 User Commands                                                 User Commands

                              28 February 2016



 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 c 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/.
















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