Feature request: Flags for inserting before/after match

[MaxGyver83]

Inserting a multi-line text after a match is not easy with sed.

Example:

$ bat file.txt
───────┬─────────────────────────────────────
       │ File: file.txt
───────┼─────────────────────────────────────
   1   │ first line
   2   │ insert after this line
   3   │ last line
───────┴─────────────────────────────────────

$ echo "$newtext"
  first new line
  second new line

$ bat file.txt | sed "/^insert after this line$/a $newtext"
first line
insert after this line
first new line
last line

Wrong: The first line of the inserted text is not indented. The second line of the inserted text is missing.

This way it works:

$ bat file.txt | sed "/^insert after this line/a \ \ first new line\n  second new line"
first line
insert after this line
  first new line
  second new line
last line

Other idea:

$ bat file.txt | sed "s/(^insert after this line$)/\1$newtext/"
sed: -e expression #1, char 47: unterminated `s' command

sd solution

$ bat file.txt | sd "(^insert after this line$)" "\$1\n$newtext"
first line
insert after this line
  first new line
  second new line
last line

Better than with sed but it could be easier.

Idea:

$ bat file.txt | sd --after "^insert after this line$" "$newtext"

And analogous:

$ bat file.txt | sd --before "^insert before this line$" "$newtext"

Do you think this would be useful? Or would you use the "\$1\n$newtext" solution in such a case?

[dev-ardi]

I think $1\n$newtext is a perfectly good solution