CODEWITHSUNDEEP
sedinsertmultiline
Alfe
Alfe

Reputation: 59426

How to insert sth with sed just once

I'm trying to substitute the first empty line in my input file with a multiline block, i. e. out of

one
two

three
four

five
six

I want to create

one
two

foo

three
four

five
six

For this I tried this sed script:

sed '/^$/i\
\
foo'

But it inserts at /each/ empty line.

How can I tweak this call to sed so that it inserts just at the first occurrence of an empty line? Is there a way to tell sed that now the rest of the input should just be copied from to the output?

I do not want to switch to awk or other shell tools like read in a loop or similar. I'm just interested in the use of sed for this task.

Upvotes: 1

Views: 46

Answers (2)

Casimir et Hippolyte
Casimir et Hippolyte

Reputation: 89557

You can loop and print lines until the end of the file:

sed '/^$/{i\
\
foo
:a;n;ba}' file

Upvotes: 3

Alfe
Alfe

Reputation: 59426

I found a way by replacing the i with a s command:

sed '0,/^$/s//\
foo\
/'

But I would prefer a solution using the i command because not everything I could want to do after the search might be easily replaceable with an s.

Upvotes: 1

Related Questions