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  main-
       tained  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 exe-
       cutable 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 begin-
       ning 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 any-
            thing else.  If multiple -C options are specified, each is  inter-
            preted  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 interest-
            ing 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  com-
            mands,  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  vari-
            ables 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 argu-
            ments 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 dependen-
            cies,  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 syn-
            chronization 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 spec-
            ified.  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
       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, 1996-2013 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                              03 March 2012                         MAKE(1)
