regex - Escaping single quote in a sed command containing variables containing color escape codes?

Answer 1

If you want to keep the single quotes, then you need '"'"'

The first quote ends the current single quoted string. Then we have "'" which expands to a single quote. \' would also work but doesn't look as good.

The last single quote starts the quoted string again.

An alternative in your case would be "s/ is /${r}'s${x}/g" (i.e. only use double quotes).

But then, you need to use r='\\e[0;31m' because the expansion in the string will string one level of escapes.