Bash match string with regex

Question

I am using bash 4.1.10(4)-release and I trying to use a regex to match against two capital letters [AZ]{2} and then anything. So for example BXCustomerAddress , CAmaterial would be acceptable, but WarehouseMessage would not. I have the following script for testing purposes:

#!/bin/bash

if [[ "Ce" =~ [A-Z]{2} ]]; then
    echo "match"
fi

My questions are:

1. When I run this script, why does it return that I have a match?
2. Does anyone know how I could achieve my desired results?

Answer 1

Looks like you have shopt nocaseglob turned on. Turn it off using:

shopt -u nocaseglob

Now [[ "Ce" =~ [AZ]{2} ]] should not match and will return false.

Answer 2

Check the value of the shell option nocasematch :

$ shopt nocasematch
nocasematch     off

Answer 3

shopt nocasematch is probably set to on . Turn it off with

shopt -u nocasematch

From the Bash Reference Manual :

nocasematch

If set, Bash matches patterns in a case-insensitive fashion when performing matching while executing case or [[ conditional commands.

Answer 4

After trying out many different combinations, this is what gave me the expected behavior:

#!/bin/bash
# [A-Z][A-Z] will not work
# [:upper:][:upper:] will not work
# [[A-Z]][[A-Z]] will not work
# [[:upper:]][[:upper:]] does work

echo "test one"
if [[ "CA" =~ ^([[:upper:]][[:upper:]])+ ]]; then
    echo "match"
fi

echo "test two"
if [[ "Ce" =~ ^([[:upper:]][[:upper:]])+ ]]; then
    echo "match"
fi

I get the expected results of:

test one
match
test two

Thanks for everyone's help