hortitude Asked: 2012-08-23 11:40:28 +0800 CST2012-08-23 11:40:28 +0800 CST 2012-08-23 11:40:28 +0800 CST Why bracket a single letter in a grep regex? 772 I've seen several instances where people are doing this: grep [f]oobar But I don't understand why that is preferable to grep foobar regex 1 Answers Voted Best Answer Jeff Ferland 2012-08-23T11:44:47+08:002012-08-23T11:44:47+08:00 There's no reason that's preferable syntax on its own. It's sometimes used as a hack when "grepping" for a process (e.g., ps aux | grep [a]pache). Using that syntax prevents grep from matching its own command line in the process list. See How to prevent "ps" reporting its own process?
There's no reason that's preferable syntax on its own. It's sometimes used as a hack when "grepping" for a process (e.g.,
ps aux | grep [a]pache). Using that syntax prevents grep from matching its own command line in the process list.See How to prevent "ps" reporting its own process?