I have to insert some text after matching a pattern in between a line.

  core: [dev][delta3=deltafile;delta3dir=755|workpm][staging=stageingfile]

  Expected output is:

  core: [dev][delta3=deltafile;delta3dir=755|workpm][delta6=delta6file;delta6Dir=755|workpm][staging=stageingfile]

Now what I tried is below: But this is not working as expected

 sed -i 's/\<[delta3=deltafile;delta3dir=755|workpm]\>/& [delta6=delta6file;delta6Dir=755|workpm]/' file.txt

This is editing my file but [delta6...] entry gets appended abruptly after

File data is like: asdasdasdad   B-L-D-V-E-R

output is showing: asdadasdadd B-L-D-[delta6=delta6file;delta6Dir=755|workpm] -V-E-R

You need to escape the | and the opening bracket [ as these are special characters in regex.

Also, you use word boundary matching \< and \> which you don't need and might cause problems.

But still then for me it only works using sed -E (not sure yet why ...).

sed -Ei 's/\[delta3=deltafile;delta3dir=755\|workpm]/&[delta6=delta6file;delta6Dir=755|workpm]/' file.txt

or if your sed does not support & back-reference:

sed -Ei 's/(\[delta3=deltafile;delta3dir=755\|workpm])/\1[delta6=delta6file;delta6Dir=755|workpm]/' file.txt


$ echo "core: [dev][delta3=deltafile;delta3dir=755|workpm][staging=stageingfile]" \
| sed -E 's/\[delta3=deltafile;delta3dir=755\|workpm]/&[delta6=delta6file;delta6Dir=755|workpm]/'
core: [dev][delta3=deltafile;delta3dir=755|workpm][delta6=delta6file;delta6Dir=755|workpm][staging=stageingfile]
  • maybe someone can point me to why it's only working with -E ... without it, the |workpm is excluded from the match. – pLumo May 8 at 12:23
  • Thanks it worked. Issue was I was giving the pattern to match inside /\< pattern\>/ – Anish Gupta May 8 at 13:05
  • glad that it works now :-) – pLumo May 8 at 13:12
  • let's clean up the comments as they are not so useful for next users I think – pLumo May 8 at 13:13

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