Add text after certain line

Question

I have big file which has following lines

abc_a
some lines
abc_b
some lines
abc_c
some lines
abc_d
some lines
abc_e
some lines
abc_f

I want to add number incremental starting from 1 after every abc lines something like

abc_a1
some lines
abc_b2
some lines
abc_c3
some lines
abc_d4
some lines
abc_e5
some lines
abc_f6

Is it possible with sed or awk?

Satō Katsura · Accepted Answer · 2017-09-01 19:06:44Z

2

With awk:

awk '/^abc/ { $0 = $0 (++a) } 1' file

With perl:

perl -lpe '/^abc/o and s/$/++$a/e' file

or

perl -lpe '/^abc/o and $_ .= ++$a' file

With vim:

:let a=1
::g/^abc/ s/$/\=a/ | let a+=1

answered Sep 1, 2017 at 18:54

Satō Katsura

13.7k2 gold badges34 silver badges52 bronze badges

1 Answer 1