The while command in Linux

The while command is a bit like a combination of if-then and for loops. The while test command returns a 0 exit state, looping through a set of commands.

While basic format:

While Test command

Do

Other commands

Done

Example:

#!/bin/bash

Varl=5

While [$varl-GT 0]

Do

Echo $varl

varl=$[$varl-1]

Done

[Email protected] ~]#./test10.sh

5

4

3

2

1

Note: Because while is detected when the exit status is 0, the loop is stopped only if the output is not 0.

varl=$[$varl-1] The result is not 0

Using multiple test commands

#!/bin/bash

Var1=3

While Echo $var 1

[$var 1-ge 0]

Do

echo "The Is inside the loop"

var1=$[$var 1-1]

Done

[Email protected] ~]#./test11.sh

3

The is inside the loop

2

The is inside the loop

1

The is inside the loop

0

The is inside the loop

-1

In multiple-line commands, all test commands are executed in each of the failed generations, including the last one to fail the test command

The while command in Linux