What does symbol ^ do in bash?

Mr. Alex · 09-13-2010, 11:57 AM

Hi.
What does symbol ^ do in bash?

For example:

Code:

grep -c ^processor /proc/cpuinfo

GrapefruiTgirl · 09-13-2010, 11:59 AM

In regular expressions, the carat symbol means "at beginning of line"; so, in order for a match to happen with your given example above, the word "processor" must be found at the beginning of a line.

slakmagik · 09-13-2010, 03:58 PM

That's what it does in the example you cite (with grep rather than as anything specific to bash) but it's an overloaded symbol - it can also negate matches in [...] expressions or exponentiate (bc) and several other things in other contexts. Just saying that, if you see ^ in a shell script, you have to know the various contexts.

Mr. Alex · 09-14-2010, 10:17 AM

So it is called "carat symbol", right?

GrapefruiTgirl · 09-14-2010, 10:48 AM

Caret is what I most often see it referred to as, and I cannot think of another name for it, although there are probably some. Here's the wiki page: http://en.wikipedia.org/wiki/Caret

Note that I had been spelling it incorrectly, but have now corrected it: Carat --> Caret