Linux Shell Example (i)

First, the environment
System: Centos6.6 x64
Shell:bash, SH

[[email protected] ~]$ hostnameShell[[email protected] ~]$ lsb_release -aLSB Version:    :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarchDistributor ID: CentOSDescription:    CentOS release 6.6 (Final)Release:    6.6Codename:   Final[[email protected] ~]$ echo $SHELL/bin/bash[[email protected] ~]$ ifconfig eth0 |grep "t addr"| awk -F ‘[: ]+‘ ‘{print $4}‘192.168.101.110

Ii. Examples of scripts
1, Terminal printing

#!/bin/bash#The printf of Linux termnal,Include "echo,printf"#author by woon echo "The shell\`s name is $0"#examples of echo,printf#默认打印。输出换行echo "Hello World!" echo ‘Hello World!‘#echo -n参数接受不换行输出echo -n "Hello World"echo "Hello World"#-e参数接受双引号内字符串的转移列表echo "Hello\tWorld!"echo -e "Hello\tWorld!"#printf使用文本或由空格分割的参数，可指定输出的宽度、对其方式等，可以格式化输出，默认情况下，printf不输出换行printf "%-5s %-10s %-4s\n" No. NAME Markprintf "%-5s %-10s %-4s\n" 1 Lee 80printf "%-5s %-10s %-4.2f\n" 2 Woon 90.456printf "%-5s %-10s %-4.2f\n" 3 James 85.654321printf "%-5s %-10s %-5.3f\n" 4 Jeff 85.123789

Operation Result:

The shell`s name is shell_print.shHello World!Hello World!Hello WorldHello WorldHello   World!-e Hello    World!No.   NAME       Mark1     Lee        80  2     Woon       90.463     James      85.654     Jeff       85.124

2. Environment variables

#!/bin/bash#author by woon#env#获取全局环境变量env > /tmp/env_$(date +%Y%m%d).$$head -n 10 /tmp/env_$(date +%Y%m%d).$$echo "^^^^^^^^^^^^^^^^^分隔符^^^^^^^^^^^^^^^^^^^^^^" #获取单个全局变量的值echo $PATHecho "^^^^^^^^^^^^^^^^^分隔符^^^^^^^^^^^^^^^^^^^^^^"#自定义变量和自定义全局变量,删除环境变量var="Hello World"echo -n "$var" echo -n $varecho ${var}#设置全局环境变量export VAR#获取当前的shell版本echo $SHELL#orecho $0#获取变量的长度var="Hello World"echo ${#var}#变量内容的删除path=$PATHecho $pathecho "最短删除，非贪婪模式,由前向后删除"var1=${path#/*:}echo $var1echo "贪婪模式，删除匹配到最长的，由前向后删除"var2=${path##/*:}echo $var2echo "非贪婪模式%，由后向前删除"var3=${path%:*bin}echo $var3echo "贪婪模式，由后向前删除最长的"var4=${path%%:*bin}echo $var4

3. Shell Mathematical Operations

#!/bin/bash#author by woon.#数学运算sum_jia=0sum_cheng=1i=1while [ $i -le 10 ]; do     let "sum_jia+=i"     let "sum_cheng*=i"     let "i += 2"donesum_jian1=$[ sum_cheng - sum_jia]sum_jian2=$(( sum_cheng - sum_jia ))echo $sum_jiaecho $sum_chengecho $sum_jian1echo $sum_jian2

Run results
$./shell_num.sh
25
945
920
920

Linux Shell Example (i)