Re: [SSHGuard-users] Call for testing: SSHGuard 1.7.0

[Jef P. <je...@ma...>]

>What's the purpose of the 'x' in lines like these?
>
>if [ "x$2" = "x6" ]; then
>
>Since the string literals are provided, there shouldn't be an error when
>the provided strings are empty. Isn't the 'x' there to guard against an
>empty string?

That's a common idiom in shell script programming. It's to
guard against the string being check having a flag argument
that the [ command, a.k.a. test, would interpret. This
is really due to test having poorly thought out argument
syntax but what are you gonna do.

Another common idiom is to merely reverse the order of
the strings being checked:

  if [ "6" = "$2" ]; then

Putting the variable second means test won't try to interpret
it as a flag.