General:

• Open Group Shell Command Language
• How can I test for POSIX compliance of shell scripts?
• DashAsBinSh
• Bash POSIX Mode

Bashisms and syntactic analysis:

• How to make bash scripts work in dash
• Fedora “devscripts-checkbashisms” package.
• Fedora “ShellCheck” package
• vim syntax highlighting

• print/printf
• restricted shell (bash -r)
• ORA shell book
• ShellCheck
• shell debugger