Shell Programming and Scripting

Code:

^(.*,){2}.*, *[0+]{,2}91

Please tell me if I have understood correctly, trying to color code to make it obvious what I'm looking at. The above expression equates to:-

From the start of line
Zero or more characters finishing in a comma (a field to us)
Twice
Another field
Zero or more spaces
A zero or a plus character
{,2} - okay I'm stuck on this one.
Literal string 91

For the one I'm stuck on, i have something telling me about {3}, {3,} or {3,6} but not the format you have. I could guess that it is 'less than or equal to 2' but my simple testing doesn't seem to get very far.



Robin

Actually, the more I look at my code, the more I see it needs some improvements/corrections, as I didn't test it against ALL possible input constellations. It worked for the file given, also for a handful of other test cases, but there may be uncovered cases.
Anyhow, my grep (grep (GNU grep) 2.14) did not complain on that {,2}, but you may be right that this is not a usual extended regex.