Package: posh Version: 0.13.1 http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_04
"The shell shall expand all tokens in the expression for parameter expansion, command substitution, and quote removal."
Script: #!/bin/posh if (eval 'P=1 && : $((M$P=3)) && Q=500 && : $((M$Q+=1)) && : $((M$P+=1)) && [ $((M$P)) = 4 -a $((M$Q)) = 1 ]' ) 2>/dev/null then : else echo 'ERROR: The shell must be POSIX compatible' >&2 exit 1 fi echo The shell is working correctly. Expected result: The shell is working correctly. Actual result: ERROR: The shell must be POSIX compatible -- Rob. (Robert de Bath <robert$ @ debath.co.uk>) <http://www.debath.co.uk/>