The ack utility uses Perl regular expressions to efficiently search source code, with smart defaults to limit the results to what you expect.

One of the ways I use it is to search our Apache web log files. The logs capture all requests, including ones for images, style sheets, fonts, and javascript files. But usually I’m only interested in who visited which web pages, including CGI scripts.

I’ve added a Bash function to my .bashrc file, acklog, that filters out the extraneous files automatically:

# ack (grep) for scripts in apache
function acklog() {
  ack "$@" | ack -v '\.(css|eot|gif|ico|jpe?g|js|png|svg|swf|webp|woff2?|xml)[? ]'
}