Home/ Questions/Q 8914255
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-15T04:40:18+00:00

I have a command that outputs three lines like this: L1 L2 L3 I

  • 0

I have a command that outputs three lines like this:

L1
L2
L3

I need to append each of those lines into a data file for Gnuplot, where there is no “comment block”, and thus you can only prepend the “#” symbol to each line. I’m scripting this whole process in bash, how do I substitute a \n for \n# in bash?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Try and pipe your command through sed like this:

    command | sed -e "s/^/#/"

    It will replace the first character of first line with # followed by said character.

    If you also want to get stderr, then throw stderr into stdout first like this:

    command 2>&1 | sed -e "s/^/#/"

    EDIT: thanks @ДМИТРИЙ МАЛИКОВ ! I just leadend something new. I’ve updated my blocks with your even shorter expression

    • 0