Why do alternate delimiters not work with sed -e '/pattern/s/a/b/'? [duplicate]

Answer 1

You absolutely can use alternate delimiters for the matching address (/regex/), but you need to tell sed that you intend to do matching with that delimiter. The way you do this is with a leading backslash \. So your command can be:

sed -e '\|somevar|s|foo|bar|' config.h

or just as easily:

sed -e '\%somevar%s|foo|bar|' config.h

Reference: POSIX reference for sed