shell脚本编程的例子(55例子)-1_shell编程案例

#!/bin/bash

# This script is to test the usage of read

# Scriptname: ex4read.sh

echo "=== examples for testing read ==="

echo -e "What is your name? \c"

read name

echo "Hello $name"

echo

echo -n "Where do you work? "

read

echo "I guess $REPLY keeps you busy!"

echo

read -p "Enter your job title: "

echo "I thought you might be an $REPLY."

echo

echo "=== End of the script ==="

linux@LAPTOP-X280:~$ cat if.sh

#!/bin/bash

## filename: areyouok.sh

#set -x ### Turn ON debug mode ###

echo

echo -e "Hello $LOGNAME, \c"

echo    "it's nice talking to you."

echo -n "Your present working directory is: "

pwd # Show the name of present directory

echo

#set +x ### Turn OFF debug mode ###

echo -e "The time is `date +%T`!. \nBye"

echo

echo "---1st demo about if-YorN---"

echo "Are you OK ?"

read answer

# 在 if 的条件判断部分使用扩展的 test 语句 [[...]]

# 在 [[]] 中可以使用shell的通配符进行条件匹配

if  [[ $answer==[Yy]* || $answer==[Mm]aybe ]]

then  echo "Glad to hear it."

fi

echo

echo "---2ed demo about if-UPorDown---"

# if 的条件部分可以使用普通的命令进行测试

# 当命令正确执行（$?=0）返回真，否则（$?<>0）返回假

myhost=peggy0223

if ping -c1 -w2 $myhost &>/dev/null

then

  echo "$myhost is UP."

else

  echo "$myhost is DOWN."

fi

echo

echo "---3rd demo about if-IDcheck---"

## filename:  idcheck.sh

# purpose: check user id to see if user is root.

# Only root has a uid of 0.

# Format for id output:

#   uid=9496(ellie) gid=40 groups=40

#   root's uid=0

#

id=`id | awk -F'[=(]'  '{print $2}'`   # get user ID

echo "your user id is: $id"

if  (( id == 0 ))    # [ $id -eq 0 ]

then

  echo "you are superuser."

else

  echo "you are not superuser."

fi

echo

#!/bin/bash

## filename: decide_file_type.sh

# if 语句可以嵌套使用

##实现判断文件类型，如是普通文件查看具有什么权限

if [ $# -ne 1 ] && echo "Usage: $0 <filename>" ; then

        exit 1

fi

file=$1

#set -x

# Check if the file exists

if [ ! -e "$file" ]; then

  echo "$file does not exist."

  exit 1

fi

if [ -d $file ];then

        echo "$file is a directory"

elif [ -f $file ];then

        #if [ -r $file -a -w $file -a -x $file ] ; then

        #if [[ -r $file && -w $file && -x $file ]] ; then

        #       echo "You have (rwx) permissioon on $file."

        #fi

        # Check file permissions separately

        read_perm=$(stat -c "%A %u %g" "$file" | cut -c 2)

        write_perm=$(stat -c "%A %u %g" "$file" | cut -c 3)

        exec_perm=$(stat -c "%A %u %g" "$file" | cut -c 4)

        if [ "$read_perm" = "r" ]; then

          echo "this file Read permission: yes"

        else

          echo "this file Read permission: no"

        fi

        if [ "$write_perm" = "w" ]; then

          echo "this file Write permission: yes"

        else

          echo "this file Write permission: no"

        fi

        if [ "$exec_perm" = "x" ]; then

          echo "this file Execute permission: yes"

        else

          echo "this file Execute permission: no"

        fi

else

        echo "$file is neither a file nor a directory."

fi

#!/bin/sh -

set -x

if test $# -eq 0

then

        echo "Missing arguments"

else if test $1 -gt 12

then

        echo "arument too big!"

        exit

#set +x

else

#set -x

        i=$1

        j=1

        while test $i -ne 0

        do

                j=`expr $j \* $i`

                i=`expr $i - 1`

        done

        echo $j

#set +x

        fi

fi

#!/bin/sh -

#This script for variables in shell

set -x

wow="hi,boy"

ygu='YGU-dx1a'

clear

echo "$wow ,My name is beautiful girl from $ygu"

echo Home Directory: $HOME

echo command line here is:

echo $0 $*

echo Before shift operation

echo No. of arguments = $#

echo All the arguments: $*

echo \$0 = $0, \$1 = $1, \$2 = $2

shift

echo After one shift operation

echo No. of arguments: $#

echo All the arguments: $*

echo \$0 = $0, \$1 = $1, \$2 = $2

set -x

fname=/bin/date

if (test -f "$fname")then

        echo "exit"

fi

Eg8、if语句-测试询问年龄

#!/bin/bash

## filename: ask-age.sh

read  -p "How old are you?  "  age

# 使用 Shell算术运算符(())进行条件测试

if ((age<0||age>120)); then

    echo "Out of range !"

    exit 1

fi

# 使用多分支if语句

if   ((age>=0&&age<13)) ; then   echo "Child !"

elif ((age>=13&&age<20)); then   echo "Callan !"

elif ((age>=20&&age<30)); then   echo "P III !"

elif ((age>=30&&age<40)); then   echo "P IV !"

else   echo "Sorry I asked."

fi

Eg9、if语句-useronline

#!/bin/bash

## filename: useronline.sh

# bash 138-if.sh root / linux查看效果

# if 语句可以嵌套使用

if [ $# -eq 1 ] # 或 [[ $#==1 ]] 或(($#==1))

then

  if who|grep $1 >/dev/null

  then echo $1 is active.

  else echo $1 is not active.

  fi

else

  echo "Usage: $0 <username>"

  exit 1

fi

Eg10、case语句-what-lang-doulike？

#!/bin/bash

## filename: what-lang-do-you-like.sh

echo "What is your preferred scripting language?"

echo "1) bash"

echo "2) perl"

echo "3) python"

echo "4) ruby"

echo "5) I do not know !"

read lang

case $lang in

    1) echo "You selected bash"  ;;

    2) echo "You selected perl"  ;;

    3) echo "You selected python";;

    4) echo "You selected ruby"  ;;

    5) exit

esac

Eg11、case语句-yeorno？

#!/bin/bash

## filename: yesorno.sh

echo -n "Do you agree with this? [yes or no]: "

read yn

case $yn in

  [Yy] | [Yy][Ee][Ss] ) echo "Agreed."  ;;

  [Nn] | [N|n][O|o]   )

                        echo "Not agreed."

                        exit 1

                        ;;

   *)                   echo "Invalid input." ;;

esac

Eg12、case语句-“一键备份”

#!/bin/bash

## filename: all_in_one_backup.sh

# A shell script to backup mysql, webserver and files.

# opt=$1

case $1 in

   sql) echo "Running mysql backup using mysqldump tool..." ;;

  sync) echo "Running backup using rsync tool..."           ;;

   git) echo "Running backup using gistore tool..."         ;;

   tar) echo "Running tape backup using tar tool..."        ;;

     *)

        echo "Backup shell script utility"

        echo "Usage: $0 {sql|sync|git|tar}"

        echo "  sql  : Run mySQL backup utility."

        echo "  sync : Run web server backup utility."

        echo "  git  : Run gistore backup utility."

        echo "  tar  : Run tape backup utility."

        ;;

esac

Eg13、foreach语句-使用字面字符串列表作为 WordList

#!/bin/bash

## filename: for1--constant_as_list.sh

# 使用字面字符串列表作为 WordList

for x in centos ubuntu gentoo opensuse

do   echo "$x" ; done

# 若列表项中包含空格必需使用引号括起来

for x in Linux "Gnu Hurd" FreeBSD "Mac OS X"

do  echo "$x" ; done

for x in ls "df -h" "du -sh"

do

    echo "==$x==" ; eval $x

done

Eg14、foreach语句-使用变量作为 WordList

#!/bin/bash

## filename: for2--variable_as_list.sh

# 使用变量作为 WordList

i=1; weekdays="Mon Tue Wed Thu Fri"

for day in $weekdays ; do

  echo "Weekday $((i++)) : $day"

done

OSList="Linux ‘Gnu Hurd’ FreeBSD ‘Mac OS X’"

for x in $OSList Others ; do

  echo "$x"

done

Eg15、foreach语句-使用位置参数变量 $@ 作为 WordList

in $@ 可以省略作为 WordList

#!/bin/bash

## filename: for3--pp_as_list.sh

# 使用位置参数变量 $@ 作为 WordList， in $@ 可以省略

#执行：bash 152-foreach.sh Mon Tue wed Thu Fri sat Sun lundi

i=1

for day ; do

  echo -n "Positional parameter $((i++)): $day "

  case $day in

    [Mm]on|[Tt]ue|[Ww]ed|[Tt]hu|[Ff]ri)

       echo " (weekday)" ;;

    [Ss]at|[Ss]un)

       echo " (WEEKEND)" ;;

    *) echo " (Invalid weekday)" ;;

  esac

done

Eg16、foreach语句-使用文件名或目录名列表作为 WordList

#!/bin/bash

## filename: for4--filenames_as_list.sh

# 使用文件名或目录名列表作为 WordList

# 将当前目录下的所有的大写文件名改为小写文件名

for filename in * ; do

  # 使用命令替换生成小写的文件名，赋予新的变量 fn

  fn=$(echo $fname | tr A-Z a-z)

  # 若新生成的小写文件名与原文件名不同，改为小写的文件名

  if [[ $fname != $fn ]] ; then mv $fname $fn ; fi

  # 上面的 if 语句与下面的命令聚合均等效

  # [[ $fname != $fn ]] && mv $fname $fn

  # [[ $fname == $fn ]] || mv $fname $fn

done

for fn in /etc/[abcd]*.conf ; do echo $fn ; done

for fn in /etc/cron.{*ly,d}/* ; do echo $fn ; done

for i in *.zip; do

  j="${i%.zip}"; mkdir "$j" && unzip -d "$j" "$i"

done

Eg17、foreach语句-使用命令的执行结果作为 WordList

#!/bin/bash

## filename: for5--command_output_as_list.sh

# 使用命令的执行结果作为 WordList

i=1

for username in `awk -F: '{print $1}' /etc/passwd`

do

    echo "Username $((i++)) : $username"

done

for line in $(cat files.txt|egrep -v "^$|^#") ; do

    echo "$line"; done

for suffix in $(seq 254)

do echo "192.168.0.${suffix}"; done

for f in $( ls /var/ ); do echo $f; done

Eg18、foreach语句-使用数值范围作为  WordList

#!/bin/bash

## filename: for6--range-of-numbers_as_list.sh

# 使用数值范围作为 WordList

mynet="192.168.0"

for num in {1..254}

do

  echo "IPAdress $num: $mynet.$num"

done

# 使用包含步长（increment）的数值范围作为 WordList

for num in {1..10..2}

do

  echo "Number: $num"

done

Eg19、foreach-扫描ip检测keysanformIPS-up-or-down

请谨慎操作，或者修改ip地址范围

#!/bin/bash

## filename: for--ssh-keyscan_from_ips.sh

# for 语句可嵌套

for i in 0 1 2 ; do

  for suffix in {1..254} ; do

    ip=192.168.$i.${suffix}

    if  ping -c1 -w2  $ip &>/dev/null

    then

       ssh-keyscan -t rsa,dsa  $ip \

           >> ~/.ssh/known_hosts

    else

        echo "Host ($ip) is DOWN."

    fi

  done

done

Eg20、批量添加50个user

请谨慎操作：

#!/bin/bash

## filename: addusers_foreach.sh

# 成批添加50个用户

for x in {1..50}      # 或 $(seq 50)

do

    useradd user${x}

    echo "centos"|passwd --stdin user${x}

    chage -d 0  user${x}

done