Our Blog

Ack, grep for Developers

By Brian J. Miller
March 19, 2009

A relatively new tool in my kit that I’ve come to use very frequently over the last 6 months or so is Ack. Notwithstanding that it is written in my preferred development language, and is maintained by a developer active in the Perl community working on some important projects, like TAP, it really does just save typing while producing Real Purdy output. I won’t go so far as to say it completely replaces grep, at least not without a learning curve and especially for people doing more “adminesque” tasks, but as a plain old developer I find its default set of configuration and output settings incredibly efficient for my common tasks. I’d go into the benefits myself, but I think the “Top 10 reasons to use ack instead of grep.” from the ack site pretty much covers it. To highlight a couple here,

1. It’s blazingly fast because it only searches the stuff you want searched.

2. Searches recursively through directories by default, while ignoring .svn, CVS and other VCS directories. Which would you rather type?

   • $ grep pattern $(find . -type f | grep -v '\.svn')
   • $ ack pattern

3. ack ignores most of the crap you don’t want to search

   • VCS directories
   • *blib*, the Perl build directory
   • backup files like *foo~* and *#foo#*
   • binary files, core dumps, etc

4. Ignoring .svn directories means that ack is faster than grep for searching through trees.

5. Lets you specify file types to search, as in –perl or –nohtml. Which would you rather type? (Note that ack’s –perl also checks the shebang lines of files without suffixes, which the find command will not.)

   • $ grep pattern $(find . -name '*.pl' -or -name '*.pm' -or -name '*.pod' | grep -v .svn)
   • $ ack --perl pattern

6. File-filtering capabilities usable without searching with ack -f. This lets you create lists of files of a given type.

7. Color highlighting of search results.

Note that there are actually 13 on their list, but I eliminated the one about that that one OS, the last is basically just for humor, and a couple are mainly relevant only to Perl users/developers.

The next time you need to search a development tree for a particular subroutine, library name, etc. give Ack a try.

tips