Variable setting help please


 
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# 1  
Old 06-28-2005
Variable setting help please

L=0

cat test.sh | while read line
do

L='expr $1 + 1'
echo $L

done

echo $l


>>> the echo $L at the end produces 0 but i actually want it to produce the number of lines - any idea why this is happening?
# 2  
Old 06-28-2005
If you trying to find out the number of lines in a file, use this simple approach

Code:
wc -l < filename

Vino
# 3  
Old 06-28-2005
Or if you want to use the while loop here it is
Code:
#! /bin/sh

L=0

while read line
do
L=$((L+1))
done < filename

echo "Total # of lines = $L"

Vino
# 4  
Old 06-28-2005
What is $1 and $l ??

I think the problem is with $l (small ) as it is not defined .
# 5  
Old 06-28-2005
When you pipe into a loop, sh actually
starts a subshell and runs the loop in that.
However any changes to variables in this
subshell can not be propagated back to the parent.
# 6  
Old 06-28-2005
Hi,

This produces an error: L=$((L+1))


also i only mixed up the 1's and L's when copying it onto the forum

cheers
# 7  
Old 06-28-2005
Quote:
Originally Posted by vino
Or if you want to use the while loop here it is
Code:
#! /bin/sh

L=0

while read line
do
L=`expr $L + 1`
done < filename

echo "Total # of lines = $L"

Try the modified RHS of L

-vino
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