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MAKE(1)				 User Commands			       MAKE(1)

       make - GNU make utility to maintain groups of programs

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

       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:


       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.

       -b, -m
	    These options are ignored for compatibility	with other versions of

       -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

       -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 re-
	    sults, 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.

	    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.

       -E string, --eval string
	    Interpret string using the eval function, before parsing any make-

       -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

       -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 ig-

       -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 re-
	    cursive make is grouped together.  If type is none output synchro-
	    nization 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  re-
	    make 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.

	    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

	    Information	 about	the disposition	of each	target is printed (why
	    the	target is being	rebuilt	and what commands are run  to  rebuild

       -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.

	    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 when an undefined variable is referenced.

       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.

       The full	documentation for make is maintained as	a Texinfo manual.   If
       the  info  and  make  programs are properly installed at	your site, the

	      info make

       should give you access to the complete manual.

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

       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 (C) 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 un-
       der 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

GNU			       28 February 2016			       MAKE(1)


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