Re: `if $(cmd);' is a positive when there's no output from cmd

[Andreas Schwab]

Herculano Einloft <hlen@ig.com.br> writes:

> Em (02:25:11), Andreas Schwab escreveu: 
>
>> 
>>> Hey all, 
>>> 
>>> $ if $(echo string >/dev/null); then echo true; fi 
>>> true 
>>> 
>>> This should be a syntax error 
>> 
>>No, it is a perfectly valid command, syntactically. That the command 
>>substitution expands to nothing has no significance any more once the 
>>command is parsed, just like shell meta characters resulting from 
>>expansions are taken literally. 
>> 
>>Andreas. 
>
> That's not true.. try: 
>
> $ echo $(echo \*) 
>
> or 
>
> $ a=*; echo "$a"; echo $a 
>
> for illustration. 

The '*' has no significance in the parser.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
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