shellcheck: refresh (#5746)

pages/common/shellcheck.md

@@ -1,20 +1,33 @@
 # shellcheck
 
 > Shell script static analysis tool.
-> More information: <https://www.shellcheck.net/>.
+> Check shell scripts for errors, usage of deprecated/insecure features, and bad practices.
+> More information: <https://www.shellcheck.net>.
 
 - Check a shell script:
 
-`shellcheck {{file.sh}}`
+`shellcheck {{path/to/script.sh}}`
 
-- Override script's shebang:
+- Check a shell script interpreting it as the specified shell dialect (overrides the shebang at the top of the script):
 
-`shellcheck --shell {{sh|bash|ksh}} {{file.sh}}`
+`shellcheck --shell {{sh|bash|dash|ksh}} {{path/to/script.sh}}`
 
-- Ignore certain errors:
+- Ignore one or more error types:
 
-`shellcheck --exclude {{SC1009}} {{file.sh}}`
+`shellcheck --exclude {{SC1009,SC1073}} {{path/to/script.sh}}`
 
-- Ignore multiple errors:
+- Also check any sourced shell scripts:
 
-`shellcheck --exclude {{SC1009,SC1073}} {{file.sh}}`
+`shellcheck --checked-sourced {{path/to/script.sh}}`
+
+- Display output in the specified format (defaults to `tty`):
+
+`shellcheck --format {{tty|checkstyle|diff|gcc|json|json1|quiet}} {{path/to/script.sh}}`
+
+- Enable one or more optional checks:
+
+`shellcheck --enable={{add-default-case|avoid-nullary-conditions}}`
+
+- List all available optional checks that are disabled by default:
+
+`shellcheck --list-optional`