Bash provides its own improved version of the [ command, doubling it to [[. It's actually a shell keyword, a special part of the Bash syntax, and not just a regular builtin command:
#!/bin/bash
myshell=bash
if [[ $myshell = 'bash' ]] ; then
printf 'Match!\n'
fi
One advantage of the [[ keyword over the [ builtin is that less quoting is required. You may notice in the preceding example that $myshell is not in double quotes.
Unfortunately, this benefit does not apply to the right-hand side of the =, ==, !=, or =~ operations. If you're testing two variables for equality, for example, you will still need to quote the one to the right of the equals sign:
[[ $myshell = "$yourshell" ]]
If you find this too confusing (or imbalanced!), ...
