feat: support shell scripts with no extension, fix perl shebang regex

CHANGELOG.md

@@ -22,6 +22,7 @@ Note: Can be used with `oxsecurity/megalinter@beta` in your GitHub Action mega-l
 - Linters enhancements
   - Trivy: Retry 10 times in case of TooManyRequests when downloading vulnerability database
   - Trivy: Embed vulnerability database in Docker Image for running trivy on internet-free network
+  - Bash/Perl: Support shell scripts with no extension and only support perl shebangs at the beginning of a file in <https://github.com/oxsecurity/megalinter/pull/4076>
 
 - Fixes
   - Add debug traces to investigate reporters activation

docs/descriptors/bash_shellcheck.md

@@ -82,6 +82,7 @@ This linter is available in the following flavors
 ### How are identified applicable files
 
 - File extensions: `.sh`, `.bash`, `.dash`, `.ksh`
+- Shebangs: `#!/usr/bin/env bash`, `#!/bin/bash`, `#!/bin/sh`
 
 <!-- markdownlint-disable -->
 <!-- /* cSpell:disable */ -->

megalinter/descriptors/bash.megalinter-descriptor.yml

@@ -7,10 +7,17 @@ descriptor_flavors:
   - c_cpp
   - formatters
 file_extensions:
+  - ""
   - ".sh"
   - ".bash"
   - ".dash"
   - ".ksh"
+file_contains_regex_extensions:
+  - ""
+file_contains_regex:
+  - "^#!/usr/bin/env bash"
+  - "^#!/bin/bash"
+  - "^#!/bin/sh"
 install:
   apk:
     - bash

megalinter/descriptors/perl.megalinter-descriptor.yml

@@ -8,8 +8,8 @@ file_extensions:
 file_contains_regex_extensions:
   - ""
 file_contains_regex:
-  - "#!/usr/bin/env perl"
-  - "#!/usr/bin/perl"
+  - "^#!/usr/bin/env perl"
+  - "^#!/usr/bin/perl"
 install:
   apk:
     - perl