Portable Shell Syntax is the scripting language syntax used by the System V Unix shell. This syntax is compatible with the heirloom shell and and is the syntax documented in many Unix books.
The checkbashisms tool detects constructs not documented in the BPB book below and constructs that do not work with ash, osh and other unix compatible shells. The syntax passed by this validation tool is a subset of the syntactical constructs defined in various POSIX specifications.
== Reference documentation ==
Reference documentation for Unix shell syntax is available in book form:
Unix Shell Programming (Yashavant P. Kanetkar. BPB Publications)
The shell I use is ash386, which is a fork of Kenneth Almquist's shell. This is the smallest Unix compatible shell that I could find that utilizes the documented syntax.