Look only for bash shebang (#4928)

* Look only for bash shebang

We have some Python scripts now so we need to move that out

* Extend script to cover ignored files and use internal tool for checking the rest

Signed-off-by: Igor <igor@armbian.com>

---------

Signed-off-by: Igor <igor@armbian.com>

.github/workflows/lint-scripts-pr.yml

@@ -32,14 +32,25 @@ jobs:
        - name: List all changed files
          run: |
 
+           # use framework internal mechanism for checking `lib` and `extensions` code  only one file is passed,
+           # and source's are followed, thus the whole project is "understood" by shellcheck.
+           # For example, when checking individual files, one variable might be thought "unused" because it
+           # is only used in another file, which does not happen when done properly.
+
+           bash lib/tools/shellcheck.sh
+
            ret=0
 
            for file in ${{ steps.changed-files.outputs.all_changed_files }}; do
-             if grep -qE "^#\!/" $file; then
 
-                 shellcheck --severity=error $file || ret=$?
+               if [[ ! "${file}" =~ lib/|extensions/|.py|.service|.rules|.network|.netdev ]]; then
+                   if grep -qE "^#\!/.*bash" $file; then
+
+                       shellcheck --severity=error $file || ret=$?
+
+                   fi
+               fi
 
-             fi
            done
 
            exit $ret