How to break out of infinite while loop in a shell script?
I want to implement the following PHP code in shell script(s):
$i=1;
while( 1 ) {
if ( $i == 1 ) continue;
if ( $i > 9 ) break;
$i++;
}
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1Since your code checks if $i == 1, and continues to the next iteration if the result is true, before incrementing $i, you actually hava an endless loop.Thomas Tschernich– Thomas Tschernich2011-11-30 09:47:37 +00:00Commented Nov 30, 2011 at 9:47
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You have an endless loop in your php code.favoretti– favoretti2011-11-30 09:49:21 +00:00Commented Nov 30, 2011 at 9:49
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2 Answers
break works in shell scripts as well, but it's better to check the condition in the while clause than inside the loop, as Zsolt suggested. Assuming you've got some more complicated logic in the loop before checking the condition (that is, what you really want is a do..while loop) you can do the following:
i=1
while true
do
if [ "$i" -eq 1 ]
then
continue
fi
# Other stuff which might even modify $i
if [ $i -gt 9 ]
then
let i+=1
break
fi
done
If you really just want to repeat something $count times, there's a much easier way:
for index in $(seq 1 $count)
do
# Stuff
done
Comments
i=1
while [ $i -gt 9 ] ; do
# do something here
i=$(($i+1))
done
Is one of the ways you can do it.
HTH
