Shell simple Use (b) loop

Record a few simple examples of loop-related

1. Wait for the expected content to be entered

#!/bin/Bashuntil["$yn"=="Yes"-O"$yn"=="YES" ] DoRead-P"Please input yes/yes to stop this progras:"yn DoneEcho "ok! You input the correct answer."

Wait to enter expected content before exiting

Also available while implementation

2. Multi-digit summation

While implementation

i=0s=0 while"$i"" ]do    i1))    s=$ (($s + $i))done  echo""

Implemented with for

#!/bin/bashs=0""  nu for ((i=1; I<= $nu; i=i+1  ) do-    s=$ (($s + $i))doneEcho " "

Execution results

3. String processing

A For loop handles file names individually

#!/bin/bash for on 'ls'do    echo  $var  Done

Execution results are as follows

For loop processing user information

#!/bin/bashusers=$ (cut -D:-f1/etc/passwd) for in $users do     ID  $username    finger $username Done

For loop find connectivity for specified IP address

#!/bin/bashnetwork="192.168.1" forSitenuinch$(seq  the  the) Do    Ping-C1-W 1${network}.${sitenu} &>/dev/NULL&& result=0|| result=1    if["$result"==0]; Then        Echo "Server ${network}.${sitenu} is up"    Else        Echo "Server ${network}.${sitenu} is down"    fi Done

Execution Result:

Shell simple Use (b) loop