1MAKE(1)                          User Commands                         MAKE(1)
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NAME

6       make - GNU make utility to maintain groups of programs
7

SYNOPSIS

9       make [OPTION]... [TARGET]...
10

DESCRIPTION

12       The  make  utility will determine automatically which pieces of a large
13       program need to be recompiled, and  issue  the  commands  to  recompile
14       them.   The  manual describes the GNU implementation of make, which was
15       written by Richard Stallman and Roland McGrath, and is currently  main‐
16       tained  by  Paul  Smith.   Our examples show C programs, since they are
17       very common, but you can use make with any programming  language  whose
18       compiler can be run with a shell command.  In fact, make is not limited
19       to programs.  You can use it to describe any task where some files must
20       be updated automatically from others whenever the others change.
21
22       To  prepare to use make, you must write a file called the makefile that
23       describes the relationships among files in your program, and the states
24       the  commands for updating each file.  In a program, typically the exe‐
25       cutable file is updated from object files, which are in  turn  made  by
26       compiling source files.
27
28       Once  a  suitable  makefile  exists,  each  time you change some source
29       files, this simple shell command:
30
31              make
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33       suffices to perform all necessary  recompilations.   The  make  program
34       uses  the  makefile  description and the last-modification times of the
35       files to decide which of the files need to be  updated.   For  each  of
36       those files, it issues the commands recorded in the makefile.
37
38       make  executes  commands  in  the makefile to update one or more target
39       names, where name is typically a program.  If no -f option is  present,
40       make  will  look for the makefiles GNUmakefile, makefile, and Makefile,
41       in that order.
42
43       Normally you should call your makefile  either  makefile  or  Makefile.
44       (We  recommend  Makefile because it appears prominently near the begin‐
45       ning of a directory listing, right near other important files  such  as
46       README.)   The  first name checked, GNUmakefile, is not recommended for
47       most makefiles.  You should use this name if you have a  makefile  that
48       is  specific  to GNU make, and will not be understood by other versions
49       of make.  If makefile is '-', the standard input is read.
50
51       make updates a target if it depends on  prerequisite  files  that  have
52       been modified since the target was last modified, or if the target does
53       not exist.
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OPTIONS

56       -b, -m
57            These options are ignored for compatibility with other versions of
58            make.
59
60       -B, --always-make
61            Unconditionally make all targets.
62
63       -C dir, --directory=dir
64            Change to directory dir before reading the makefiles or doing any‐
65            thing else.  If multiple -C options are specified, each is  inter‐
66            preted  relative to the previous one: -C / -C etc is equivalent to
67            -C /etc.  This is typically used  with  recursive  invocations  of
68            make.
69
70       -d   Print debugging information in addition to normal processing.  The
71            debugging information says which files are  being  considered  for
72            remaking,  which  file-times  are  being  compared  and  with what
73            results, which files actually need to be  remade,  which  implicit
74            rules  are considered and which are applied---everything interest‐
75            ing about how make decides what to do.
76
77       --debug[=FLAGS]
78            Print debugging information in addition to normal processing.   If
79            the  FLAGS are omitted, then the behavior is the same as if -d was
80            specified.  FLAGS may be a for all debugging output (same as using
81            -d),  b for basic debugging, v for more verbose basic debugging, i
82            for showing implicit rules, j for details on  invocation  of  com‐
83            mands,  and  m  for  debugging while remaking makefiles.  Use n to
84            disable all previous debugging flags.
85
86       -e, --environment-overrides
87            Give variables taken from the environment  precedence  over  vari‐
88            ables from makefiles.
89
90       -f file, --file=file, --makefile=FILE
91            Use file as a makefile.
92
93       -i, --ignore-errors
94            Ignore all errors in commands executed to remake files.
95
96       -I dir, --include-dir=dir
97            Specifies  a  directory  dir to search for included makefiles.  If
98            several -I options are used to specify  several  directories,  the
99            directories are searched in the order specified.  Unlike the argu‐
100            ments to other flags of make, directories given with -I flags  may
101            come directly after the flag: -Idir is allowed, as well as -I dir.
102            This syntax is allowed for compatibility with the C preprocessor's
103            -I flag.
104
105       -j [jobs], --jobs[=jobs]
106            Specifies the number of jobs (commands) to run simultaneously.  If
107            there is more than one -j option, the last one is  effective.   If
108            the  -j  option  is given without an argument, make will not limit
109            the number of jobs that can run simultaneously.
110
111       -k, --keep-going
112            Continue as much as possible after an  error.   While  the  target
113            that  failed,  and  those that depend on it, cannot be remade, the
114            other dependencies of these targets can be processed all the same.
115
116       -l [load], --load-average[=load]
117            Specifies that no new jobs (commands) should be started  if  there
118            are  others  jobs running and the load average is at least load (a
119            floating-point number).  With no argument, removes a previous load
120            limit.
121
122       -L, --check-symlink-times
123            Use the latest mtime between symlinks and target.
124
125       -n, --just-print, --dry-run, --recon
126            Print the commands that would be executed, but do not execute them
127            (except in certain circumstances).
128
129       -o file, --old-file=file, --assume-old=file
130            Do not remake the file file even if it is older than its dependen‐
131            cies,  and  do  not remake anything on account of changes in file.
132            Essentially the file is treated as very  old  and  its  rules  are
133            ignored.
134
135       -O[type], --output-sync[=type]
136            When  running multiple jobs in parallel with -j, ensure the output
137            of each job is collected together rather  than  interspersed  with
138            output from other jobs.  If type is not specified or is target the
139            output from the entire recipe for each target is grouped together.
140            If  type is line the output from each command line within a recipe
141            is grouped together.  If type is recurse  output  from  an  entire
142            recursive  make  is grouped together.  If type is none output syn‐
143            chronization is disabled.
144
145       -p, --print-data-base
146            Print the data base (rules and variable values) that results  from
147            reading the makefiles; then execute as usual or as otherwise spec‐
148            ified.  This also prints the version information given by  the  -v
149            switch  (see  below).   To  print  the data base without trying to
150            remake any files, use make -p -f/dev/null.
151
152       -q, --question
153            ``Question mode''.  Do not run any commands,  or  print  anything;
154            just  return  an exit status that is zero if the specified targets
155            are already up to date, nonzero otherwise.
156
157       -r, --no-builtin-rules
158            Eliminate use of the built-in implicit rules.  Also clear out  the
159            default list of suffixes for suffix rules.
160
161       -R, --no-builtin-variables
162            Don't define any built-in variables.
163
164       -s, --silent, --quiet
165            Silent operation; do not print the commands as they are executed.
166
167       -S, --no-keep-going, --stop
168            Cancel  the  effect  of  the  -k  option.  This is never necessary
169            except in a recursive make where -k might be  inherited  from  the
170            top-level make via MAKEFLAGS or if you set -k in MAKEFLAGS in your
171            environment.
172
173       -t, --touch
174            Touch files (mark them up to date without  really  changing  them)
175            instead  of  running their commands.  This is used to pretend that
176            the commands were done, in order to  fool  future  invocations  of
177            make.
178
179       --trace
180            Information  about  the disposition of each target is printed (why
181            the target is being rebuilt and what commands are run  to  rebuild
182            it).
183
184       -v, --version
185            Print  the version of the make program plus a copyright, a list of
186            authors and a notice that there is no warranty.
187
188       -w, --print-directory
189            Print a message containing the working directory before and  after
190            other  processing.   This  may  be useful for tracking down errors
191            from complicated nests of recursive make commands.
192
193       --no-print-directory
194            Turn off -w, even if it was turned on implicitly.
195
196       -W file, --what-if=file, --new-file=file, --assume-new=file
197            Pretend that the target file has just been  modified.   When  used
198            with  the -n flag, this shows you what would happen if you were to
199            modify that file.  Without -n, it is almost the same as running  a
200            touch  command  on the given file before running make, except that
201            the modification time is changed only in the imagination of make.
202
203       --warn-undefined-variables
204            Warn when an undefined variable is referenced.
205

EXIT STATUS

207       GNU make exits with a status of zero if all makefiles were successfully
208       parsed  and no targets that were built failed.  A status of one will be
209       returned if the -q flag was used and  make  determines  that  a  target
210       needs  to  be  rebuilt.  A status of two will be returned if any errors
211       were encountered.
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SEE ALSO

214       The full documentation for make is maintained as a Texinfo manual.   If
215       the  info  and  make  programs are properly installed at your site, the
216       command
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218              info make
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220       should give you access to the complete manual.
221

BUGS

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

226       This manual page contributed by Dennis Morse  of  Stanford  University.
227       Further updates contributed by Mike Frysinger.  It has been reworked by
228       Roland McGrath.  Maintained by Paul Smith.
229
231       Copyright © 1992-1993, 1996-2016 Free Software Foundation,  Inc.   This
232       file is part of GNU make.
233
234       GNU  Make  is  free  software; you can redistribute it and/or modify it
235       under the terms of the GNU General Public License as published  by  the
236       Free  Software Foundation; either version 3 of the License, or (at your
237       option) any later version.
238
239       GNU Make is distributed in the hope that it will be useful, but WITHOUT
240       ANY  WARRANTY;  without even the implied warranty of MERCHANTABILITY or
241       FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General  Public  License
242       for more details.
243
244       You should have received a copy of the GNU General Public License along
245       with this program.  If not, see http://www.gnu.org/licenses/.
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249GNU                            28 February 2016                        MAKE(1)
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