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Why this is not working in expected way?

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# 1  
Old 12-07-2009
Error Why this is not working in expected way? (a question about the default bash behavior)
Code:
total=0

seq 1 5 | while read i ; do
total=$(($total+$i))
echo $total
done

echo $total

This outputs:
Code:
1
3
6
10
15
0

whereas I am expecting:
Code:
1
3
6
10
15
15

My bash version:
Code:
> bash -version
GNU bash, version 3.1.17(1)-release (x86_64-redhat-linux-gnu)

meharo
Last edited by meharo; 12-07-2009 at 06:15 AM.. Reason: As per the forum guidelines...
# 2  
Old 12-07-2009
Because the behavior of your script is undefined and bash decided to have the left side of a pipeline to be run in the original shell process and not the rightmost, a poor decision IMHO.

Switch to ksh if you want your script to behave as you expect.
# 3  
Old 12-07-2009
a better syntax would be
Code:
total=0
for in $(seq 5) ; do
total=$(($total+$i))
echo $total
done
echo $total

# 4  
Old 12-07-2009
That should read
Code:
for i in $(seq 5) ...

# 5  
Old 12-07-2009
Have a look here for information about how to get around the pipe thing in bash.
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