Need Help Extracting A Substring

snkmchnb · 09-16-2008, 07:38 AM

I'm writing a shell script that uses cat to combine a bunch of csv files into one. What I'm trying to do is extract a 16 digit number with a known prefix out of each line and display that only. I've got it using grep to display only the lines with the number but how would you suggest extracting/displaying just the number from the string? I'm sure it could/should be done with awk or sed but I'm relatively knew to the commands and I'm horrible at regex.

Any help would be appreciated. Thanks!

matthewg42 · 09-16-2008, 08:19 AM

If the pattern you pass to grep matches just the part of the line you are interested in, you can use the -o option to the GNU grep to output just that part of the matching lines.

If not, there are a multitude of ways to extract parts of a line. cut, awk, sed, perl. Which is best depends on the nature of the problem, your platform and personal preference. If you describe in more detail what you are trying to do (i.e. include example input, output and metrics such as data set size), I'm happy to make a suggestion.

harry2006 · 09-16-2008, 08:25 AM

a more detailed explanation of ur prob ll put more light on how to attack the problem...but as matthew rightly suggested u can make use of simple comands like cut...keep life simple...i'll do teh job...but again it all depends on ur requirement...so if u r still stuck with the prob...state ur problem more clearly...

snkmchnb · 09-16-2008, 08:28 AM

Quote:

Originally Posted by matthewg42

If the pattern you pass to grep matches just the part of the line you are interested in, you can use the -o option to the GNU grep to output just that part of the matching lines.

If not, there are a multitude of ways to extract parts of a line. cut, awk, sed, perl. Which is best depends on the nature of the problem, your platform and personal preference. If you describe in more detail what you are trying to do (i.e. include example input, output and metrics such as data set size), I'm happy to make a suggestion.

the grep -o worked perfectly, thanks!