NAME

m4 - macro processor

SYNOPSIS

m4 [,OPTION/]... [,FILE/]...

DESCRIPTION

Process macros in FILEs. If no FILE or if FILE is `-', standard input is read.

Mandatory or optional arguments to long options are mandatory or optional for short options too.

Operation modes:

--help
display this help and exit
--version
output version information and exit
-E, --fatal-warnings
once: warnings become errors, twice: stop execution at first error
-i, --interactive
unbuffer output, ignore interrupts
-P, --prefix-builtins
force a `m4_' prefix to all builtins
-Q, --quiet, --silent
suppress some warnings for builtins
--warn-macro-sequence[=,REGEXP/]
warn if macro definition matches REGEXP,
default \$\({[^}]*}\|[0-9][0-9]+\)
-W, --word-regexp=,REGEXP/
use REGEXP for macro name syntax

Preprocessor features:

-D, --define=NAME[=,VALUE/]
define NAME as having VALUE, or empty
-I, --include=,DIRECTORY/
append DIRECTORY to include path
-s, --synclines
generate `#line NUM "FILE"' lines
-U, --undefine=,NAME/
undefine NAME

Limits control:

-g, --gnu
override -G to re-enable GNU extensions
-G, --traditional
suppress all GNU extensions
-H, --hashsize=,PRIME/
set symbol lookup hash table size [509]
-L, --nesting-limit=,NUMBER/
change nesting limit, 0 for unlimited [0]

Frozen state files:

-F, --freeze-state=,FILE/
produce a frozen state on FILE at end
-R, --reload-state=,FILE/
reload a frozen state from FILE at start

Debugging:

-d, --debug[=,FLAGS/]
set debug level (no FLAGS implies `aeq')
--debugfile[=,FILE/]
redirect debug and trace output to FILE (default stderr, discard if empty string)
-l, --arglength=,NUM/
restrict macro tracing size
-t, --trace=,NAME/
trace NAME when it is defined

FLAGS is any of:

a
show actual arguments
c
show before collect, after collect and after call
e
show expansion
f
say current input file name
i
show changes in input files
l
say current input line number
p
show results of path searches
q
quote values as necessary, with a or e flag
t
trace for all macro calls, not only traceon'ed
x
add a unique macro call id, useful with c flag
V
shorthand for all of the above flags

If defined, the environment variable `M4PATH' is a colon-separated list of directories included after any specified by `-I'.

Exit status is 0 for success, 1 for failure, 63 for frozen file version mismatch, or whatever value was passed to the m4exit macro.

AUTHOR

Written by Rene' Seindal.

REPORTING BUGS

Report bugs to: bug-m4 [at] gnu.org
GNU M4 home page: <http://www.gnu.org/software/m4/>
General help using GNU software: <http://www.gnu.org/gethelp/>

COPYRIGHT

Copyright © 2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

SEE ALSO

The full documentation for m4 is maintained as a Texinfo manual. If the info and m4 programs are properly installed at your site, the command
info m4

should give you access to the complete manual.