TECHPULP | How to write infinite loop in Bash

October 17, 2008

By: Neo

In Category Bash

The while-do-done statement can be used to program an infinite loop in bash. The following sample shows how it can be done.

#!/bin/bash

while [ 1 ];
do
echo I am in infinite loop. Press Ctrl+C to stop me
done

The break statement can be used to exit the while loop. The following sample code breaks away from while loop after iterating 10 times.

#!/bin/bash

i=1
while [ 1 ];
do
        i=`expr $i + 1`
        echo loop $i
        if [ "$i" == "10" ]; then
                echo Exiting while loop after iterating $i times
                break
        fi
done

echo end of shell script

The following will be the output when the above script is run.

[neo@techpulp ~]# sh iloop.sh
loop 2
loop 3
loop 4
loop 5
loop 6
loop 7
loop 8
loop 9
loop 10
Exiting while loop after iterating 10 times
end of shell script
[neo@techpulp ~]#

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