On 2/21/19 10:00 AM, Rockefeller, Harry wrote: > CYGWIN_NT-6.1 HARRYR-PC 3.0.0(0.336/5/3) 2019-02-16 13:21 x86_64 Cygwin > GNU bash, version 4.4.12(3)-release (x86_64-unknown-cygwin) > > #!/bin/bash > A="A" > B="A" > if [ $A!=$B ]; then > echo -e "not identical" > fi > if [ $A==$B ]; then > echo -e "identical" > fi > exit 0 > > Running this script gives > not identical > identical > > Both tests are true.
Well, yeah, but it's not a bug in bash, but in your script. Whitespace for argument separation is essential in [. You've provided exactly one argument, and in one-argument mode, you are testing for non-empty strings. Since both strings "A!=B" and "A==B" are non-empty strings, the if clause is taken both times. You meant to provide three arguments, and with proper quoting, and using the portable spelling of equality (if you want to port your script to more than just bash): [ "$A" != "$B" ] [ "$A" = "$B" ] -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
