Testing for strings, and numbers

Aart Koelewijn aart at mtack.xs4all.nl
Fri Nov 13 13:50:31 UTC 2009


On Fri, 13 Nov 2009 05:24:13 -0800, Ray Parrish wrote:

> Hello,
> 
> I am writing a bash script and I would like to test $1 to see if it
> begins with the string "http://" but I am not coming up with a method of
> doing so.
> 
> Also I would like to know how to test $1 to see if it begins with a
> numeric digit.
> 
> All of my attempts so far have been stymied, and I can't seem to find
> the excellent bash reference I had been using before, and am trying to
> navigate a couple of less than excellent references that do not include
> sections on string handling.
> 
> Could someone help me with this please?
> 
> Thanks, Ray Parrish

I think you could use sed for that, testing with ^http or ^[0-9]. To only 
look at the first line you can use sed '1 q'. ^ means look if the line 
start with the expression. sed can easely be integrated in a bash script, 
but how you have to do it depends on your needs. It all can be done with 
perl too, some will find that more convienent

Aart





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