adding blank lines to a file - awk

Ricardo Pan :
> Hello ... how do I add a blank line after some defined number of
> lines?
>
> Regards
>
> Example: I have a file with 100 lines, after 10 lines I would like to
> add a blank line.
>
> 1st line
> 2nd line
> 3rd line
> 4th line
> 5th line
> 10th line
> blank line
> 11th line
> 12th line
> ...
> 20th line
> blank line
> 21st line
> 22nd line
> 23rd line
> ...
> 30th line
> blank line
> ...
> ...
> ...
> blank line
> 91st line
> 92nd line
> 93rd line
> ...
> 100th line


awk '{ print } NR % 10 == 0 { print "" }' input

Vassilis

Ricardo Pan wrote:
> Hello ... how do I add a blank line after some defined number of
> lines?
>
> Regards
>
> Example: I have a file with 100 lines, after 10 lines I would like to
> add a blank line.

awk 'ORS=NR%10?"\n":"\n\n"'

Janis

>
> 1st line
> 2nd line
> 3rd line
> 4th line
> 5th line
> 10th line
> blank line
> 11th line
> 12th line
> ...
> 20th line
> blank line
> 21st line
> 22nd line
> 23rd line
> ...
> 30th line
> blank line
> ...
> ...
> ...
> blank line
> 91st line
> 92nd line
> 93rd line
> ...
> 100th line
>