How to replace this regex with a empty using sed

Question

For performance reasons I have to use sed to replace some text in a file and I just can't get it working. This is the search query (that works in C#) to be replaced:

<oTimer.*?/>

First off I can't seem to correctly escape the / i am using single quotes with double backslash so

<oTimer.*?\\/>

And then I get to the problem on how to replace this with a empty string.

sed 's/<oTimer.*?\\/g>

doesn't seem to do it.

Answer 1

• If <oTimer.*?/> is your regexp, note that <oTimer/>something else <anothertag?> will also match. Is this desired? Maybe you are looking for an html parser instead?

• Are you sure about the question mark? It has no special meaning in basic regular expressions, so your pattern needs to end in (unusual) ?/>

• You need a single backslash to escape the slash, but in this case it's easier to read using a different delimiter to your s command (you are free to choose one!): s_regex_replacement with /_

• If you want to replace with an empty string, you still need the third delimiter (the second and the third surround the replacement string, so for an empty replacement you have two delimiters with nothing in between).

• In total, I suspect you are looking for something like sed 's_<oTimer[^>]*/>__g'

Answer 2

First, sed doesn't support non greedy quantifier *?.

Second, you should change the substitution operator's delimiter:

sed 's~<oTimer[^>]*/>~~g'

Answer 3

Don't use sed for this since it doesn't understand non-greedy matching. You can use perl instead:

perl -pe 's|<oTimer.*?/>||g' file.in > file.out

Or, to edit the file in place:

perl -i.bak -pe 's|<oTimer.*?/>||g' file.in