shell programs using different types of loops.

Shell supports a set of loops such as for, while and until to execute a set of statements repeatedly. The body of the loop is contained between do and done statement. The for loop doesn't test a condition, but uses a list instead.

for variable in list

do

statements

done

The while loop executes the statements as long as the condition remains true.

while [ condition ]

do

statements

done

The until loop complements the while construct in the sense that the statements are executed as long as the condition remains false.

until [ condition ]

do

statements

done