Delete all comments in a file using sed

Question

How would you delete all comments using sed from a file(defined with #) with respect to \'#\' being in a string?

This helped out a lot except for the string portion.

Answer 1

As you have pointed out, sed won't work well if any parts of a script look like comments but actually aren't. For example, you could find a # inside a string, or the rather common $# and ${#param}.

I wrote a shell formatter called shfmt, which has a feature to minify code. That includes removing comments, among other things:

$ cat foo.sh
echo $# # inline comment
# lone comment
echo '# this is not a comment'
[mvdan@carbon:12] [0] [/home/mvdan]
$ shfmt -mn foo.sh
echo $#
echo '# this is not a comment'

The parser and printer are Go packages, so if you'd like a custom solution, it should be fairly easy to write a 20-line Go program to remove comments in the exact way that you want.