UNIX for Dummies Questions & Answers

You can also do:

Code:

grep \<[1-9][0-9][0-9][0-9]\>

To find a number beginning with 1 through 9 and then any 3 numbers after it preceded and followed by a space, IE 2354 blah blah

Really? How does that work?

In any case the numbers should come at the beginning of the line (^).

the \< \> (escaped < > characters) are regular expressions for word boundries, so if you wanted a 4 number string that was not part of a string but stood alone, you could use them.. If you want the line to begin with that string you could do:

Code:

 
^[1-9][0-9][0-9][0-9]\>

This would match "2456 something something" but not "2456something something" In the example above I used only one, so if you wanted to match the string attached to the beginning of a word with white space to it's left you could do:

Code:

\<2456something

Is this standard, or a GNU extension?