Why am i getting an unexpected operator error in bash string equality test? [duplicate]

Answer 1

Add the following to the top of your script:

#! /bin/bash

In bash, == is the same as = when used inside of single brackets. This is, however, not portable. So you should explicitly tell the shell to use bash as the script's interpreter by putting #! /bin/bash at the top of the script.

Alternatively, do your string comparisons using =. Note that the == operator behaves differently when used inside of double-brackets than when inside of single-brackets (see the link).

Answer 2

You can't use == for single bracket comparisons ([ ]). Use single = instead. Also you must quote the variables to prevent expansion.

if [ "$bn" = README ]; then

If you use [[ ]], that could apply and you wouldn't need to quote the first argument:

if [[ $bn == README ]]; then