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Old 20th May 2013
J65nko J65nko is offline
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Join Date: May 2008
Location: Budel - the Netherlands
Posts: 3,505
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It is the pipeline that is the cause for spawning the sub-shell:

Code:
#!/bin/sh

VAR=Old

pgrep sh | wc -l

echo Entering the loop
# echo A | while read REPLY; do
while read REPLY; do
    echo Here
    VAR=New
    echo "Inside while ... done loop: VAR = $VAR"
    pgrep sh | wc -l
    if [ "X$REPLY" = X"Q" ] ; then 
       break
    fi
done

echo Back to main program: VAR = $VAR
pgrep sh | wc -l
Running it:
Code:
$  ./test2.sh 
       9
Entering the loop
a
Here
Inside while ... done loop: VAR = New
       9
a
Here
Inside while ... done loop: VAR = New
       9
Q
Here
Inside while ... done loop: VAR = New
       9
Back to main program: VAR = New
       9
So no change in the number of shells here and the variable now has been modified as expected.
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