Linux操作系統(tǒng)編寫(xiě)條件和循環(huán)語(yǔ)句腳本編寫(xiě)條件和循環(huán)語(yǔ)句腳本（1）在用戶(hù)主目錄中創(chuàng)建腳本文件test-condition01.sh，使用test命令和方括號(hào)進(jìn)行條件控制，檢查文件是否存在、文件是否可寫(xiě)等。[huawei@openeuler~]#vitest-condition01.sh#檢查文件是否存在mkdir~/testfileiftest-e~/testfile;thenecho"Fileexists"elseecho"Filedoesnotexist"fi#檢查文件是否可寫(xiě)touch~/www.opencloud.funiftest-w~/www.opencloud.fun;thenecho"Fileiswritable"elseecho"Fileisnotwritable"fi#檢查兩個(gè)整數(shù)是否相等a=10b=11iftest$a-eq$b;thenecho"aisequaltob"elseecho"aisnotequaltob"fi#檢查字符串是否為空string=www.opencloud.funiftest-z"$string";thenecho"Stringisempty"elseecho"Stringisnotempty"fi#檢查兩個(gè)字符串是否相等string1=www.opencloud.funstring2=opencloud.funiftest"$string1"="$string2";thenecho"Stringsareequal"elseecho"Stringsarenotequal"fi#檢查文件是否存在mkdir~/testfileif[-e~/testfile];thenecho"Fileexists"elseecho"Filedoesnotexist"fi#檢查文件是否可寫(xiě)touch~/www.opencloud.funif[-w~/www.opencloud.fun];thenecho"Fileiswritable"elseecho"Fileisnotwritable"fi#檢查兩個(gè)整數(shù)是否相等a=10b=11if["$a"-eq"$b"];thenecho"aisequaltob"elseecho"aisnotequaltob"fi#檢查字符串是否為空string=www.opencloud.funif[-z"$string"];thenecho"Stringisempty"elseecho"Stringisnotempty"Fi編寫(xiě)條件和循環(huán)語(yǔ)句腳本（2）在用戶(hù)主目錄中創(chuàng)建腳本文件if-user.sh，實(shí)現(xiàn)創(chuàng)建用戶(hù)和設(shè)置用戶(hù)密碼的功能。[huawei@openeuler~]#viif-user.sh#!/bin/bashecho"Pleaseenteryourusername:"readusername#檢查用戶(hù)是否存在if!id"$username">/dev/null2>&1;thenecho"Userdoesnotexist,pleasecreatetheuser"read-p"Pleaseenteryourusername:"usernameif[-z"$username"];thenif[-z"$password"];thensudouseradd$usernamesudoecho$password|passwd$username--stdinsudoecho"User$usernamecreatedsuccessfully"fifiexit1fiecho"Pleaseenteryourpassword:"readpasswordif[-z"$password"];thenecho"Passwordisempty,pleaseenteravalidpassword."exit1else#為用戶(hù)設(shè)置新密碼

sudoecho"$username:$password"|chpasswdsudoecho"Passwordchangedsuccessfully"fi編寫(xiě)條件和循環(huán)語(yǔ)句腳本（3）在用戶(hù)主目錄中創(chuàng)建腳本文件case-user.sh，檢查磁盤(pán)、內(nèi)存、CPU等的使用情況。[huawei@openeuler~]#vicase-user.sh#!/bin/bashecho"請(qǐng)選擇一個(gè)操作:"echo"1.查看磁盤(pán)使用情況"echo"2.查看內(nèi)存使用情況"echo"3.查看CPU使用情況"echo"4.退出"read-p"請(qǐng)輸入數(shù)字（1-4）:"choicecase"$choice"in1)df-h;;2)free-h;;3)top-bn1|head-n10;;4)echo"退出程序"exit0;;*)echo"無(wú)效輸入";;esac編寫(xiě)條件和循環(huán)語(yǔ)句腳本（4）在用戶(hù)主目錄中創(chuàng)建腳本文件for-backup.sh。通過(guò)for語(yǔ)句遍歷備份目錄列表，依次對(duì)每個(gè)目錄進(jìn)行備份，并將備份文件傳輸?shù)竭h(yuǎn)程服務(wù)器中。[huawei@openeuler~]#vifor-backup.sh#!/bin/bashbackup_dirs=("/etc""/mnt""/tmp")dest_dir="/backup"dest_server="node1"backup_date=$(date+%b-%d-%y)echo"Startingbackupof:${backup_dirs[@]}"foriin"${backup_dirs[@]}";dosudotar-Pczf/tmp/$i-$backup_date.tar.gz$iif[$?-eq0];thenecho"$ibackupsucceeded."elseecho"$ibackupfailed."fiscp/tmp/$i-$backup_date.tar.gz$dest_server:$dest_dirif[$?-eq0];thenecho"$itransfersucceeded."elseecho"$itransferfailed."fidonesudorm/tmp/*.gzecho"Backupisdone."編寫(xiě)條件和循環(huán)語(yǔ)句腳本（5）在用戶(hù)主目錄中創(chuàng)建腳本文件while-useradd.sh。使用while語(yǔ)句和計(jì)數(shù)器變量迭代創(chuàng)建用戶(hù)并設(shè)置密碼，同時(shí)將每個(gè)用戶(hù)的用戶(hù)名和密碼寫(xiě)入文件，以便后續(xù)參考和使用。[huawei@openeuler~]#viwhile-useradd.sh#!/bin/bash#創(chuàng)建一個(gè)文件來(lái)存儲(chǔ)用戶(hù)名和密碼password_file="passwords.txt">"$password_file"#清空文件內(nèi)容count=1#循環(huán)創(chuàng)建10個(gè)用戶(hù)while[$count-le10]do#生成隨機(jī)密碼

password=$(opensslrand-base6412|tr-dc'a-zA-Z0-9'|head-c10)#創(chuàng)建用戶(hù)

username="user$count"useradd"$username"#設(shè)置密碼

echo"$username:$password"|chpasswd#將用戶(hù)名和密碼寫(xiě)入文件

echo"Username:$username">>"$passw