UNIX for Beginners Questions & Answers

Yes, because it works as designed:

Code:

sed '13s/^/[...]

means: go to line 13 and apply the following substitution (s/...) to this line. So, yes, it works on line 13 and nothing else.

If you want to employ a logic like search for a certain line and add some new line after that it is a little more complicated: you need the "n" command (read next line into pattern space). The following example uses GNU-sed:

Code:

sed '/^ABC/ {
              n
              s/^/new text\n/
         }' input

Every line beginning with with "ABC" will get a new line after it containing "new text". The only problem here (in order to keep the example simple) is that this would not work properly if the last line of a file would be "ABC".

I hope this helps.

bakunin