UNIX for Dummies Questions & Answers

Is there way to use sed to change only one occurence in a colon separated line?

I would like to change a file from

*:*:rex:rex
*:*:simon:rex

to

*:*:rex:mabry
*:*:simon:rex

In this case, anchoring to end of line would seem to work fabulously. In the general case, you have to come up with a regular expression which indicates where in the line you want the substutution to happen, obviously.

Hi.

I try to match the tool to the problem. Whenever I encounter a situation that deals with delimited columns or fields, I reach for awk, because awk makes it so easy to deal with such structures.

As era said, if you're dealing with the last field (or the first field), then sed can work, but trying to manipulate a field in the middle is where awk will shine. It may seem like awk is a difficult tool to learn, but you can start with simple constructs. Look at a few of the posts here, or Google for awk tutorial for lots of hits.

This forum has an abundance of folks who are well-versed in awk, and are willing to help. To get help, you need only to show what you have tried and how it failed ... cheers, drl