NAME
    make - GNU make utility to maintain groups of programs

SYNOPSIS
    make [ -f makefile ] [ option ] ... target ...

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.texinfo.

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. 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, 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 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 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.

    -C 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.

    -e  Give variables taken from the environment precedence over vari-
   ables from makefiles.

    -f file
   Use file as a makefile.

    -i  Ignore all errors in commands executed to remake files.

    -I 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
   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  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

    -l 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.

    -n  Print the commands that would be executed, but do not execute
   them.

    -o 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.

    -p  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 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  Eliminate use of the built-in implicit rules. Also clear out the
   default list of suffixes for suffix rules.

    -s  Silent operation; do not print the commands as they are executed.

    -S  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 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.

    -v  Print the version of the make program plus a copyright, a list of
   authors and a notice that there is no warranty.

    -w  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.

    -W 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.

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.