Quick: If you shout "regular expressions" in a crowd of Linux users, what happens? Answer: Everyone will tell you the right way to use them, and every answer will be different. Regular expressions ...

You can specify patterns right down to the character. The most common Linux regular expression command is grep. You can search for basic patterns: This will match an "f," followed by any other ...

The most obvious command for doing math on the Linux command line is expr as in “expression”. It works with arithmetic expressions and provides nearly instant responses to your requests even ...

With Linux or Unix ... one of the most used command line tools which is why I use it as the example in this article. But grep isn’t the only program that uses regular expressions.

Beneath the surface of the well-known Linux commands lies a treasure trove ... For more advanced users, the ability to use regular expressions will allow you to find just about anything.

When working with regular expressions in a shell script the norm is to use grep or sed or some other external command/program. Since version 3 of bash (released in 2004) there is another option: ...

The asterisk doesn't actually do anything in this command, because it's not following any character. The dot in regex means "any character", so ... Shawn is Associate Editor here at Linux Journal, and ...

Authors and commenters might chain 10 commands together with pipes and ... words alone without ever really explaining how regular expressions work or the most common uses of sed itself.