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

[Kevin Z. <kev...@gm...>]

On 07/28/2016 15:24, Jef Poskanzer wrote:
>> 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.

Ahh, I see. I'm glad someone is looking over my shell scripts.

> 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.

I think I like this better.

Thanks,
Kevin

-- 
Kevin Zheng
kev...@gm... | ke...@be... | PGP: 0xC22E1090