Man page 1 : m4

• --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 \$\({[^}]*}\|[0-9][0-9]+\)

• -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

• -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]

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

• -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

• 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.