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

The following is the list of filetypes supported by ack.  You can
specify a file type with the --type=TYPE format, or the --TYPE
format.  For example, both --type=perl and --perl work.

Note that some extensions may appear in multiple types.  For example,
.pod files are both Perl and Parrot.

    --[no]asm       .s .S
    --[no]binary    Binary files, as defined by Perl's -B op (default: off)
    --[no]cc        .c .h .xs
    --[no]cpp       .cpp .m .h .C .H
    --[no]csharp    .cs
    --[no]css       .css
    --[no]elisp     .el
    --[no]haskell   .hs .lhs
    --[no]html      .htm .html .shtml
    --[no]java      .java
    --[no]js        .js
    --[no]lisp      .lisp
    --[no]mason     .mas
    --[no]ocaml     .ml .mli
    --[no]parrot    .pir .pasm .pmc .ops .pod .pg .tg
    --[no]perl      .pl .pm .pod .tt .ttml .t
    --[no]php       .php .phpt
    --[no]python    .py
    --[no]ruby      .rb .rhtml .rjs
    --[no]scheme    .scm
    --[no]shell     .sh .bash .csh .ksh .zsh
    --[no]sql       .sql .ctl
    --[no]tcl       .tcl
    --[no]tex       .tex .cls .sty
    --[no]tt        .tt .tt2
    --[no]vim       .vim
    --[no]xml       .xml .dtd .xslt
    --[no]yaml      .yaml .yml