On Fri, Nov 04, 2011 at 05:30:52PM +0100, Roman Rakus wrote: > On 11/04/2011 09:09 AM, flong@dell1.localdomain wrote: > > [[ "-h" =~ '^-h' ]] ; echo $? > > Should return 0, but instead returns 1. > > > It was bug in previous versions of bash in fedora and RHEL. > This behavior is correct now.
Expanding this slightly: when a character in the operand on the right hand side of the =~ operator is quoted, that character no longer retains its Regular Expression meaning, and instead becomes a string literal. This also applies to quoted substitutions, as in [[ $a =~ "$b" ]]. If you want the value of $b to be treated as an ERE, don't quote it. [[ "-h" =~ '^-h' ]] compares the string -h to the string ^-h and of course they are not equal. [[ "-h" =~ ^-h ]] does what you expected. re='^-h' [[ "-h" =~ $re ]] is the preferred way to write the code. It's even written in the manual this way.
