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Piping output to while read

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# 1  
Old 11-26-2005
Piping output to while read
Hi. Im using cat to output the contents of a file, then piping it to my while read loop.In this loop variables get assigned values. However when i try to use the variables outside the loop their values has been reset.I understand about subshells etc. but I have no idea how to "preserve" the variables.Any help is greatly appreciated. Smilie
# 2  
Old 11-26-2005
Switch to ksh or bash. The behavior you describe will only happen with the Bourne shell.
# 3  
Old 11-26-2005
Quote:
Originally Posted by Perderabo
Switch to ksh or bash. The behavior you describe will only happen with the Bourne shell.
I also receive this behaviour with bash. Piping into a while loop results in this behaviour, however, redirecting stdin into the while loop doesn't.

Code:
bash-3.00$ while read line; do
>   bar=100
> done < foo.pl
bash-3.00$ echo $bar
100
bash-3.00$ cat foo.pl | while read line; do
>   bar=200
> done
bash-3.00$ echo $bar
100

Cheers
ZB
# 4  
Old 11-26-2005
Just tried it and you're right, ZB. bash loses variable assignments in loops under this condition. pdKSH does too. Apparently ksh alone can handle this situation.
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