Loops in Unix You may use different loops based on the situation. They are: #1) Unix For loop statement Example: This program will add 1+2+3+4+5 and result will be 15 for i in 1 2 3 4 5 do sum=`expr $sum + $i` done echo $sum #2) Unix While loop statement Example: This program will print the value of ‘a’ five times, from 1 to 5. a=1 while [ $a -le 5 ] do echo “value of a=” $a a=`expr $a + 1` done #3) Unix Until loop statement This program will print the value of ‘a’ two times from 1 to 2. a=1 until [ $a -ge 3 ] do echo “value of a=” $a a=`expr $a + 1` done While running these loops, there may be a need to break out of the loop in some condition before completing all the iterations or to restart the loop before completing the remaining statements. This can be achieved with the ‘break’ and ‘continue’ statements. The following program illustrates the ‘break’ operation: num=1 while [ $num -le 5 ] do read var if [ $var -lt 0 ] then ...
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