SC2074

Can't use =~ in [ ]. Use [[..]] instead.

Problematic code:

[ "$input" =~ DOC[0-9]*\.txt ] && echo "match"

Correct code:

[[ "$input" =~ DOC[0-9]*\.txt ]] && echo "match"

Rationale:

=~ only works in [[ .. ]] tests. It does not work with test or [ in any shell.

If you're targeting POSIX sh, rewrite in terms of case or grep instead.

Exceptions:

None.