'Either or' type of regex in Emacs occur function?

Question

My version of Emacs is 23.0.91.1. Ubuntu did not catch up with 23.1, yet. Anyway,

I have an strace capture, and wanted to see file descriptors usage. So, wanted to see "^(open|socket)" regexp on occur, but didn't work. Grouping regexp does not work in Emacs regexp?

Answer 1

Bare parentheses and pipe characters are not metacharacters in Emacs; you need a preceding backslash to make them do grouping and alternation, respectively. So, you want:

^\(open\|socket\)