SAMS Teach Yourself Unix in 10 Minutes

Using ^ (Again) and $

Let's learn how to do more with REs, but match the start and end of a line with the ^ (again) and $ characters.

In order to uniquely match the years specified in the sample file, you can use the start-of-line and end-of-line regular expression characters to stop grep from matching items you do not want matched. For example, if my phone number was in the sample file, I would not want it specified and I can do that with REs.

The characters ^ and $ are commonly referred to as anchors. To anchor something would be to fix something firmly and stably. They will anchor a pattern to the start or end of a line. 1899 and 1999 are both at the beginning of a line so doing this will not be difficult, and will show you the way these REs ...