MAKE(1) LOCAL USER COMMANDS MAKE(1)
NAME
make - GNU make utility to maintain groups of programs
SYNOPSIS
make [ -f makefile ] [ options ] ... [ targets ] ...
WARNING
This man page is an extract of the documentation of GNU make. It is updated only occasionally,
because the GNU project does not use nroff. For complete, current documentation, refer to the Info
file make.info which is made from the Texinfo source file make.texi.
DESCRIPTION
The purpose of the make utility is to 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 most 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, typi-cally typically
cally 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 data base 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 data base.
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.
-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 equiva-lent equivalent
lent 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.
-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
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.
-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 any-thing anything
thing on account of changes in file. Essentially the file is treated as very old and its rules
are ignored.
-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.
-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 com-mands. commands.
mands. This is used to pretend that the commands were done, in order to fool future invocations
of make.
-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 GNU Make Manual
BUGS
See the chapter `Problems and Bugs' in The GNU Make Manual.
AUTHOR
This manual page contributed by Dennis Morse of Stanford University. It has been reworked by Roland
McGrath. Further updates contributed by Mike Frysinger.
COPYRIGHT
Copyright (C) 1992, 1993, 1996, 1999 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 Gen-eral General
eral Public License as published by the Free Software Foundation; either version 2, 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 GNU make; see the file
COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
MA 02110-1301, USA.
GNU 22 August 1989 MAKE(1)
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