Usage: ack [OPTION]... PATTERN [FILES]

Search for PATTERN in each source file in the tree from cwd on down.
If [FILES] is specified, then only those files/directories are checked.
ack may also search STDIN, but only if no FILES are specified, or if
one of FILES is "-".

Default switches may be specified in ACK_OPTIONS environment variable.

Example: ack -i select

Searching:
  -i, --ignore-case     Ignore case distinctions
  -v, --invert-match    Invert match: select non-matching lines
  -w, --word-regexp     Force PATTERN to match only whole words
  -Q, --literal         Quote all metacharacters; expr is literal

Search output:
  -l, --files-with-matches
                        Only print filenames containing matches
  -L, --files-without-match
                        Only print filenames with no match
  -o                    Show only the part of a line matching PATTERN
                        (turns off text highlighting)
  --output=expr         Output the evaluation of expr for each line
                        (turns off text highlighting)
  -m, --max-count=NUM   Stop after NUM matches
  -H, --with-filename   Print the filename for each match
  -h, --no-filename     Suppress the prefixing filename on output
  -c, --count           Show number of lines matching per file

  --group               Group matches by file name.
                        (default: on when used interactively)
  --nogroup             One result per line, including filename, like grep
                        (default: on when the output is redirected)

  --[no]color           Highlight the matching text (default: on unless
                        output is redirected, or on Windows)

Context control:
  -B, --before-context=NUM
  -A, --after-context=NUM
  -C, --context=NUM
                        Print NUM lines of context before and/or after
                        matching lines

File finding:
  -f                    Only print the files found, without searching.
                        The PATTERN must not be specified.
  --sort-files          Sort the found files lexically.

File inclusion/exclusion:
  -n                    No descending into subdirectories
  -a, --all             All files, regardless of extension (but still skips
                        blib, CVS, RCS, SCCS, .svn, _darcs and .git dirs)
  --perl                Include only Perl files.
  --type=perl           Include only Perl files.
  --noperl              Exclude Perl files.
  --type=noperl         Exclude Perl files.
                        See "ack --help type" for supported filetypes.
  --[no]follow          Follow symlinks.  Default is off.

Miscellaneous:
  --help                This help
  --man                 Man page
  --version             Display version & copyright
  --thpppt              Bill the Cat