shell script problem

[Matthew Seaman]

On 23/12/2012 09:43, Polytropon wrote:
> On Sun, 23 Dec 2012 10:34:34 +0100, Polytropon wrote:
>> First, the lines with "read" have to be:
>>
>> cat /foo/bar.txt | while read $LINE1
>>
>> 	cat /foo/bar/foo/bar.txt | while read $LINE2
>>
>> Reason: $LINE1 and $LINE2 will be evaluated here, they are "empty
>> string", causing "read" to throw an error.
> 
> Excuse me - I made a mistake! Of course those two lines
> have to be:
> 
> cat /foo/bar.txt | while read LINE1
> 
> and
> 
> 	cat /foo/bar/foo/bar.txt | while read LINE2
> 
> The $ infront of the variable names have to be removed.
> The variable _name_, not its content, has to be provided
> to "read" as a parameter.
> 
> The script so far:
> 
> 
> 
> #!/bin/sh
> 
> cat foo.txt | while read LINE1
> do
> 	cat bar.txt | while read LINE2
> 	do
> 		if [ "$LINE1" = "$LINE2" ]; then
> 			sw="1"
> 			echo "Current value of sw is : " $sw
> 			break
> 		fi
> 	done
> 	echo "Value of sw is : " $sw
> 	if [ "$sw" = "0" ]; then
> 		echo "DO SOMETHING!"
> 	fi
> 	sw="0"
> done
> 
> 

Hmmm.... I'd just like to draw your attention to the comm(1) program,
which lets you find lines common to two files, or only in one or other
of a pair of inputs, very easily.  The only slight gotcha is that the
input files have to be sorted.

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.
PGP: http://www.infracaninophile.co.uk/pgpkey


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