The `s6-test` program

s6-test evaluates an expression and indicates the result via its exit status.

Interface

     s6-test expression...

s6-test acts as the generic test utility, but it diverges from the specification on one point: if an argument starts with a backslash, this backslash is ignored (and the argument cannot be an operation). This is a simple disambiguation technique that has unfortunately not been chosen by the standard.

s6-test accepts an arbitrary number of arguments.

Exit codes

0: the test is true
1: the test is false
100: wrong usage
101: internal error (should never happen, warrants a bug-report)
111: system call failure

Posixness

s6-test is not suitable as a Single Unix test program; however, if your arguments never start with a backslash, it exhibits the exact same behaviour.

Non-standard expressions

-v VAR : tests whether the VAR variable is defined in the current environment.
string =~ pattern : tries to match string against extended regular expression pattern. True if any part of string matches pattern; in order to match whole strings, you must anchor pattern with ^ and $ markers.

Notes