awk command with v=line number as variable

Asked Feb 08 '21 at 20:19

Active Feb 08 '21 at 20:25

Viewed 23 times

i have a file called shazad.txt [root@ans archive]# cat shazad.txt

aaa

aaaa

aaaaa

aaaaaa

aaaaaaa

i want to add some data at specific line number which works if i explicitly say NR==10 [root@ans archive]# awk 'NR==10{print "ppppppppppppppppppppppppppppppppppppppppp"}1' shazad.txt

aaa

aaaa

aaaaa

aaaaaa

aaaaaaa

aaaaaaaa

aaaaaaaaa

ppppppppppppppppppppppppppppppppppppppppp

aaaaaaaaaa

but when i pass the value as variable it doesnt do anything, not sure what is going on

also, if there is any other way like sed to insert at a particular line using a variable name as reference.

[root@ans archive]# echo $abc

[root@ans archive]# awk 'NR==$abc{print "ppppppppppppppppppppppppppppppppppppppppp"}1' shazad.txt

aaa

aaaa

aaaaa

aaaaaa

aaaaaaa

aaaaaaaa

aaaaaaaaa

aaaaaaaaaa

edited Feb 08 '21 at 20:25

asked Feb 08 '21 at 20:19

Shazad Khan

You missed the `-v` option and `$abc` is not interpreted inside single quotes. For the part with the variable use double quotes instead. – Socowi Feb 08 '21 at 20:21
@Socowi that's not the only problem. – Ed Morton Feb 08 '21 at 20:22
The $abc is not expanded when it is eclosed in single quotes. Try `echo '$abc'` – Jerry Jeremiah Feb 08 '21 at 20:24
so what can be done? is there a solution to achieve this? @Socowi – Shazad Khan Feb 11 '21 at 01:17
Um, yeah. The solution is in the [linked duplicate](https://stackoverflow.com/questions/19075671/how-do-i-use-shell-variables-in-an-awk-script). Use `awk -v n="$abc" 'NR==n {...`. – Socowi Feb 11 '21 at 08:45

awk command with v=line number as variable

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