Bash: add multiple lines after a first occurene of matched pattern in the file

Question

How to acheive this with awk/sed?

Input:

zero
one
two
three
four

output:

zero
one
    one-one
    one-two
    one-three
two
three
four

Note: I need actual tab to be included in the new lines to be added.

Is the fact that each of your added lines starts with "one" in any way related to the fact that the line you're searching for starts with "one"? — Ed Morton, Nov 12 '13 at 21:14

score 4 · Answer 1 · answered Nov 12 '13 at 20:32

4

With GNU sed, you can use the a\ command to append lines after a match (or i\ to insert lines before a match.

sed '/one/a\ \tone-one\n\tone-two\n\tone-three' file 
zero
one
    one-one
    one-two
    one-three
two
three
four

answered Nov 12 '13 at 20:32

Anders Lindahl

41,582
9
89
93

score 2 · Answer 2 · edited May 23 '17 at 11:59

The title states 'after the first occurrence' (I presume occurene is a typo), however, other answers don't seem to cater this requirement and due to the unique nature of the sample set, it is not that obvious when you test.

If we change the sample set to

zero
one
three
one
four
five
one
six
seven
one

Then we would need something like awk '/one/ && !x {print $0; print "\tone-one\n\tone-two\n\tone-three"; x=1;next} 1', which produces

zero
one
    one-one
    one-two
    one-three
    two
three
one
four
five
one
six
seven
one

Actually, this and that answers provide some more options as well.

anubhava · Answer 3 · 2013-11-12T20:25:51.883

1

Using awk:

awk '1; /one/{print "\n\tone-one\n\tone-two\n\tone-three"}' file
zero
one
        one-one
        one-two
        one-three
two
three
four

edited Nov 12 '13 at 20:25

answered Nov 12 '13 at 20:20

anubhava

761,203
64
569
643

`'1; /one/ {print "..."}'` would have worked as well (without the need for next). – Etan Reisner Nov 12 '13 at 20:22
@EtanReisner: That would have printed `one` twice. – anubhava Nov 12 '13 at 20:24
1

Not if you didn't include `$0` in your print. – Etan Reisner Nov 12 '13 at 20:24
This inserts after _every_ occurrence, not just the requested _first_ occurrence. – Generic Ratzlaugh Nov 01 '22 at 16:09
Nope it inserts after `one` text only. – anubhava Nov 01 '22 at 16:29

Bash: add multiple lines after a first occurene of matched pattern in the file

3 Answers3