Re: adding leading zeros to a filename

From: Janis Papanagnou (Janis_Papanagnou_at_hotmail.com)
Date: 01/30/05 

Date: Sun, 30 Jan 2005 21:10:40 +0100

alan@ljubljana.agtrz.com wrote:
> On 2005-01-28, Kevin Rodgers <ihs_4664@yahoo.com> wrote:
>>rupert wrote:
>>
>>>Basically I know nothing about shell scripting. I'm guessing I can
>>>write such a beast that will list the contents of a directory
>>
>>for file in *.jpg; do
>> ...
>>done
>>
>>or
>>
>>ls *.jpg | while read file; do
>>...
>>done
>
> How do you handle the case where directory contains no *.jpg.
>
> I get an error. Is there an idiom for the test?

ls *.jpg 2>/dev/null | while read file; do ... ; done

will not display an error and will not iterate the loop since the read
gets an EOF; this is often the desired behaviour. If you want a separate
handling for the error case you may catch the test before you enter the
loop as a separate command; test operators are [...] and [[...]].

Janis

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