1MAKE(1) User Commands MAKE(1)
2
6 make - GNU Make utility to maintain groups of programs
7
9 make [OPTION]... [TARGET]...
10
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 To prepare to use make, you must write a file called the makefile that
23 describes the relationships among files in your program, and provides
24 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 Once a suitable makefile exists, each time you change some source
29 files, this simple shell command:
30 make
32 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 make executes commands in the makefile to update one or more targets,
39 where target is typically a program. If no -f option is present, make
40 will look for the makefiles GNUmakefile, makefile, and Makefile, in
41 that order.
42 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 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.
54
56 -b, -m
57 These options are ignored for compatibility with other versions of
58 make.
59 -B, --always-make
61 Unconditionally make all targets.
62 -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 -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 re‐
73 sults, 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 --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 any or all of the following names, comma-
81 or space-separated. Only the first character is significant: the
82 rest may be omitted: all for all debugging output (same as using
83 -d), basic for basic debugging, verbose for more verbose basic de‐
84 bugging, implicit for showing implicit rule search operations,
85 jobs for details on invocation of commands, makefile for debugging
86 while remaking makefiles, print shows all recipes that are run
87 even if they are silent, and why shows the reason make decided to
88 rebuild each target. Use none to disable all previous debugging
89 flags.
90 -e, --environment-overrides
92 Give variables taken from the environment precedence over vari‐
93 ables from makefiles.
94 -E string, --eval string
96 Interpret string using the eval function, before parsing any make‐
97 files.
98 -f file, --file=file, --makefile=FILE
100 Use file as a makefile.
101 -i, --ignore-errors
103 Ignore all errors in commands executed to remake files.
104 -I dir, --include-dir=dir
106 Specifies a directory dir to search for included makefiles. If
107 several -I options are used to specify several directories, the
108 directories are searched in the order specified. Unlike the argu‐
109 ments to other flags of make, directories given with -I flags may
110 come directly after the flag: -Idir is allowed, as well as -I dir.
111 This syntax is allowed for compatibility with the C preprocessor's
112 -I flag.
113 -j [jobs], --jobs[=jobs]
115 Specifies the number of jobs (commands) to run simultaneously. If
116 there is more than one -j option, the last one is effective. If
117 the -j option is given without an argument, make will not limit
118 the number of jobs that can run simultaneously.
119 --jobserver-style=style
121 The style of jobserver to use. The style may be one of fifo,
122 pipe, or sem (Windows only).
123 -k, --keep-going
125 Continue as much as possible after an error. While the target
126 that failed, and those that depend on it, cannot be remade, the
127 other dependencies of these targets can be processed all the same.
128 -l [load], --load-average[=load]
130 Specifies that no new jobs (commands) should be started if there
131 are others jobs running and the load average is at least load (a
132 floating-point number). With no argument, removes a previous load
133 limit.
134 -L, --check-symlink-times
136 Use the latest mtime between symlinks and target.
137 -n, --just-print, --dry-run, --recon
139 Print the commands that would be executed, but do not execute them
140 (except in certain circumstances).
141 -o file, --old-file=file, --assume-old=file
143 Do not remake the file file even if it is older than its dependen‐
144 cies, and do not remake anything on account of changes in file.
145 Essentially the file is treated as very old and its rules are ig‐
146 nored.
147 -O[type], --output-sync[=type]
149 When running multiple jobs in parallel with -j, ensure the output
150 of each job is collected together rather than interspersed with
151 output from other jobs. If type is not specified or is target the
152 output from the entire recipe for each target is grouped together.
153 If type is line the output from each command line within a recipe
154 is grouped together. If type is recurse output from an entire re‐
155 cursive make is grouped together. If type is none output synchro‐
156 nization is disabled.
157 -p, --print-data-base
159 Print the data base (rules and variable values) that results from
160 reading the makefiles; then execute as usual or as otherwise spec‐
161 ified. This also prints the version information given by the -v
162 switch (see below). To print the data base without trying to re‐
163 make any files, use make -p -f/dev/null.
164 -q, --question
166 ``Question mode''. Do not run any commands, or print anything;
167 just return an exit status that is zero if the specified targets
168 are already up to date, nonzero otherwise.
169 -r, --no-builtin-rules
171 Eliminate use of the built-in implicit rules. Also clear out the
172 default list of suffixes for suffix rules.
173 -R, --no-builtin-variables
175 Don't define any built-in variables.
176 -s, --silent, --quiet
178 Silent operation; do not print the commands as they are executed.
179 --no-silent
181 Cancel the effect of the -s option.
182 -S, --no-keep-going, --stop
184 Cancel the effect of the -k option.
185 -t, --touch
187 Touch files (mark them up to date without really changing them)
188 instead of running their commands. This is used to pretend that
189 the commands were done, in order to fool future invocations of
190 make.
191 --trace
193 Information about the disposition of each target is printed (why
194 the target is being rebuilt and what commands are run to rebuild
195 it).
196 -v, --version
198 Print the version of the make program plus a copyright, a list of
199 authors and a notice that there is no warranty.
200 -w, --print-directory
202 Print a message containing the working directory before and after
203 other processing. This may be useful for tracking down errors
204 from complicated nests of recursive make commands.
205 --no-print-directory
207 Turn off -w, even if it was turned on implicitly.
208 --shuffle[=MODE]
210 Enable shuffling of goal and prerequisite ordering. MODE is one
211 of none to disable shuffle mode, random to shuffle prerequisites
212 in random order, reverse to consider prerequisites in reverse or‐
213 der, or an integer <seed> which enables random mode with a spe‐
214 cific seed value. If MODE is omitted the default is random.
215 -W file, --what-if=file, --new-file=file, --assume-new=file
217 Pretend that the target file has just been modified. When used
218 with the -n flag, this shows you what would happen if you were to
219 modify that file. Without -n, it is almost the same as running a
220 touch command on the given file before running make, except that
221 the modification time is changed only in the imagination of make.
222 --warn-undefined-variables
224 Warn when an undefined variable is referenced.
225
227 GNU Make exits with a status of zero if all makefiles were successfully
228 parsed and no targets that were built failed. A status of one will be
229 returned if the -q flag was used and make determines that a target
230 needs to be rebuilt. A status of two will be returned if any errors
231 were encountered.
232
234 The full documentation for make is maintained as a Texinfo manual. If
235 the info and make programs are properly installed at your site, the
236 command
237 info make
239 should give you access to the complete manual.
241
243 See the chapter ``Problems and Bugs'' in The GNU Make Manual.
244
246 This manual page contributed by Dennis Morse of Stanford University.
247 Further updates contributed by Mike Frysinger. It has been reworked by
248 Roland McGrath. Maintained by Paul Smith.
249
251 Copyright © 1992-1993, 1996-2023 Free Software Foundation, Inc. This
252 file is part of GNU Make.
253 GNU Make is free software; you can redistribute it and/or modify it un‐
255 der the terms of the GNU General Public License as published by the
256 Free Software Foundation; either version 3 of the License, or (at your
257 option) any later version.
258 GNU Make is distributed in the hope that it will be useful, but WITHOUT
260 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
261 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
262 for more details.
263 You should have received a copy of the GNU General Public License along
265 with this program. If not, see https://www.gnu.org/licenses/.
266GNU 26 May 2023 MAKE(1)