1. 创建可执行文件 t2.sh 并打印 "hello world!"
xiluhua@localhost ~ $ mkdir tscriptsxiluhua@localhost ~ $ cd tscripts/xiluhua@localhost ~/tscripts $ echo '#!/bin/bash' >> t2.shxiluhua@localhost ~/tscripts $ echo 'echo "hello world!"' >>t2.sh xiluhua@localhost ~/tscripts $ chmod +x *xiluhua@localhost ~/tscripts $ ./t2.sh hello world!
2. 运行可执行文件的 3中方法
xiluhua@localhost ~/tscripts $ ./t2.sh hello world!xiluhua@localhost ~/tscripts $ sh t2.sh hello world!xiluhua@localhost ~/tscripts $ /bin/sh t2.sh hello world!
3. 使用变量
xiluhua@localhost ~/tscripts $ name=zhangsanxiluhua@localhost ~/tscripts $ echo $namezhangsanxiluhua@localhost ~/tscripts $ echo ${name}zhangsanxiluhua@localhost ~/tscripts $ 变量名外面的花括号是可选的，可加可不加，加花括号是为了帮助解释器识别变量的边界
4. for 循环打印 java c c++ php scala，体会 ${} 的作用
#!/bin/bashfor skill in java c c++ php scala;do echo "I am good at $skill"done echo "======================================="for skill in java c c++ php scala;do echo "I am good at $skillScript"done echo "======================================="for skill in java c c++ php scala;do echo "I am good at ${skill}Script"done 5. 只读变量，unset 不能取消
xiluhua@localhost ~/tscripts $ name=jackxiluhua@localhost ~/tscripts $ readonly namexiluhua@localhost ~/tscripts $ echo $namejackxiluhua@localhost ~/tscripts $ name=Tom-bash: name: readonly variablexiluhua@localhost ~/tscripts $ unset name-bash: unset: name: cannot unset: readonly variablexiluhua@localhost ~/tscripts $
6. 非只读变量可以取消，取消后打印为空
xiluhua@localhost ~/tscripts $ unname=Jerryxiluhua@localhost ~/tscripts $ unset unnamexiluhua@localhost ~/tscripts $ echo $unname
7. 单引号
①. 单引号里的任何字符都原样输出，单引号变量中的变量是无效的；②. 单引号字符串中不能出现单引号，对单引号使用转义符后也不行xiluhua@localhost ~ $ name='Leo'xiluhua@localhost ~ $ echo '$name'$namexiluhua@localhost ~ $ echo '$'name'>
8. 双引号
①. 双引号里可以有变量②. 双引号里可以出现转义字符xiluhua@localhost ~ $ echo "I am $name"I am Leoxiluhua@localhost ~ $ echo "\\I am $name \\"\I am Leo \
9. 拼接字符串
xiluhua@localhost ~ $ echo "He is $name"He is Leoxiluhua@localhost ~ $ echo "$name is handsome"!Leo is handsome!xiluhua@localhost ~ $ echo "$name is handsome!"-bash: !": event not found
10. 获取字符串长度
xiluhua@localhost ~ $ echo ${#name}3 11. 提取字符串
xiluhua@localhost ~ $ echo ${name:0:2}Le 12. 查找子字符串
xiluhua@localhost ~ $ expr index $name e2
13. 数组
bash支持一维数组（不支持多维数组），并且没有限定数组的大小。类似与C语言，数组元素的下标由0开始编号。获取数组中的元素要利用下标，下标可以是整数或算术表达式，其值应大于或等于0。
14. 声明数组并打印一
xiluhua@localhost ~ $ arr=(a b c)xiluhua@localhost ~ $ echo $arraxiluhua@localhost ~ $ echo ${arr[0]}axiluhua@localhost ~ $ echo ${arr[2]}cxiluhua@localhost ~ $ echo ${arr[@]}a b c 15. 声明数组并打印二
xiluhua@localhost ~ $ arr=()xiluhua@localhost ~ $ echo ${arr[@]} xiluhua@localhost ~ $ arr[0]=xxiluhua@localhost ~ $ echo ${arr[0]}xxiluhua@localhost ~ $ arr[1]=yxiluhua@localhost ~ $ arr[2]=zxiluhua@localhost ~ $ echo ${arr[@]} # 打印数组全部内容x y zxiluhua@localhost ~ $ echo ${arr[*]} # 打印数组全部内容x y z
16. 获取数组长度
xiluhua@localhost ~ $ echo ${#arr[@]}3 17. 获取数组单个元素的长度
xiluhua@localhost ~ $ arr[3]=yesxiluhua@localhost ~ $ echo ${arr[3]}yesxiluhua@localhost ~ $ echo ${#arr[3]}3 18. shell 传递参数
#!/bin/bash# auth: xiluhua# date: 2017-01-14echo 'args 0,file name: '$0echo 'args 1: '$1echo 'args 2: '$2echo 'args 3: '$3
19. 特殊字符
#!/bin/bash# auth: xiluhua# date: 2017-01-14echo 'shell exercise'echo 'first arg: '$1echo 'args total number: '$#echo 'args are: '$*echo 'current process id: '$$echo 'the last proess id run in the background: '$!echo 'args are: '$@echo 'shell options: '$-echo 'command run status: '$?
20. $* 与$@ 的区别
相同点：都是引用所有参数。不同点：只有在双引号中体现出来。假设在脚本运行时写了三个参数 1、2、3，， "*" 等价于 "1 2 3"（传递了一个参数）， "@" 等价于 "1" "2" "3"（传递了三个参数）
21. $* 与$@ 的区别实例
#!/bin/bash# auth: xiluhua# date: 2017-01-14 echo '--- $* DEMO ---'for i in "$*";do echo 'i: '$idone echo '--- $@ DEMO ---'for i in "$@";do echo 'i: '$idone
22. 新建可执行文件
sbash='#!/bin/bash'sauth='# auth: xiluhua'sdate="# date: $(date +%Y-%m-%d)"shead="$sbash\n$sauth\n$sdate"
23. expr
原生bash不支持简单的数学运算，但是可以通过其他命令来实现，例如 awk 和 expr，expr 最常用。
expr 是一款表达式计算工具，使用它能完成表达式的求值操作。
- 表达式和运算符之间要有空格，例如 2+2 是不对的，必须写成 2 + 2，这与我们熟悉的大多数编程语言不一样。
- 完整的表达式要被 ` ` 包含，注意这个字符不是常用的单引号，在 Esc 键下边。
例如，两个数相加(注意使用的是反引号 ` 而不是单引号 ')：
xiluhua@localhost ~/tscripts $ expr 2 + 24xiluhua@localhost ~/tscripts $ sum=`expr 2 + 2`xiluhua@localhost ~/tscripts $ echo $sum4
24. expr 加减乘除运算
xiluhua@localhost ~/tscripts $ a=20xiluhua@localhost ~/tscripts $ b=10xiluhua@localhost ~/tscripts $ sum=`expr $a + $b`xiluhua@localhost ~/tscripts $ echo $sum30xiluhua@localhost ~/tscripts $ diff=`expr $a - $b`xiluhua@localhost ~/tscripts $ echo $diff10xiluhua@localhost ~/tscripts $ prod=`expr $a \* $b`xiluhua@localhost ~/tscripts $ echo $prod200xiluhua@localhost ~/tscripts $ odd=`expr $a / $b`xiluhua@localhost ~/tscripts $ echo $odd2
25. expr 和算术运算符实例
注意：乘号(*)前边必须加反斜杠(\)才能实现乘法运算；
#!/bin/bash# auth: xiluhua# date: 2017-01-14 a=20b=10 echo '--- expr DEMO ---'echo 'a=20'echo 'b=10'sum=`expr $a + $b`dif=`expr $a - $b`pro=`expr $a \* $b`odd=`expr $a / $b` echo 'sum: '$sumecho 'dif: '$difecho 'pro: '$proecho 'odd: '$odd if [ $a == $b ]then echo 'a equal b'fi if [ $a != $b ]then echo a "don't equal b"fi
26. 逻辑运算符
#!/bin/bash# auth: xiluhua# date: 2017-01-14a=20b=10 echo '--- bool operators DEMO ---'echo 'a=20'echo 'b=10' if [ $a != $b ]then echo 'a !equal b'else echo 'a equal b'fi if [ $a -gt $b -a $a -lt 30 ]then echo 'a gt 10 but lt 30'else echo '! ag 10 but lt 30'fi if [ $b -eq 10 -o $b -gt 9 ]then echo 'b ge 9'else echo '!b ge 9'fi
26. 字符串运算符
#!/bin/bash# auth: xiluhua# date: 2017-01-14a=abcb=efgc='' echo "--- string DEMO ---"echo "a=abc"echo "b=efg" if [ $a = $b ]then echo "a eq b"else echo "a !eq b"fi if [ $a != $b ]then echo "a !eq b"else echo "a eq b"fi if [ -z $a ]then echo "a's length is 0"else echo "a's length is ${#a}"fi if [ -z $c ]then echo "c's length is 0"else echo "c's length is ${#c}"fi if [ -n $a ]then echo "a's length is ${#a}"else echo "a's length is 0"fi if [ -n $c ]then echo "c's length is ${#c}"else echo "c's length is 0"fi if [ $a ]then echo "a's length is ${#a}"else echo "a's length is 0"fi if [ $c ]then echo "c's length is ${#c}"else echo "c's length is 0"fi 27. 关系运算符
#!/bin/bash# auth: xiluhua# date: 2017-01-14 file='/home/xiluhua/tscripts' echo '--- file test operators DEMO ---'echo $file if [ -e $file ]then echo "$file is exist"else echo "$file is !exist"fi if [ -d $file ]then echo "$file is a directory"fi if [ -f $file ]then echo "$file is a file"fi if [ -s $file ]then echo "$file is empty"fi if [ -r $file ]then echo "$file is readable"else echo "$file is !readable"fi if [ -w $file ]then echo "$file is writable"else echo "$file is !writable"fi if [ -x $file ]then echo "$file is excecutable"else echo "$file is !excecutable"fi
28. echo 显示转义字符
echo "\"It is a test\""
29. echo 开启换行
xiluhua@localhost ~/tscripts $ echo -e "Tom \n is from China"Tom is from China
30. echo 不开启换行
#!/bin/bash# auth: xiluhua# date: 2017-01-14echo -e "Tom is from China, \c"echo "he is programmer."
31. printf
#!/bin/bash# auth: xiluhua# date: 2017-01-14printf "%-10s %-8s %-10s\n" name gender weight[kg]printf "%-10s %-8s %-4.2f\n" Jack male 68.1234printf "%-10s %-8s %-4.2f\n" Tom male 78.6512printf "%-10s %-8s %-4.2f\n" Susan female 80
32. printf
%s %c %d %f都是格式替代符%-10s 指一个宽度为10个字符（-表示左对齐，没有则表示右对齐），任何字符都会被显示在10个字符宽的字符内，如果不足则自动以空格填充，超过也会将内容全部显示出来。%-4.2f 指格式化为小数，其中.2指保留2位小数。
33. while (1)
#!/bin/bash# auth: xiluhua# date: 2017-01-15 n1=$1 echo '--- while DEMO ---'echo 'n1=$n1' while (( $n1 <= 5 ))do echo $n1 n1=`expr $n1 + 1` # 等同于 let 'n1++'done
34. while (2)
#!/bin/bash# auth: xiluhua# date: 2017-01-15 while truedo read -p 'please input a film: ' film if [ -z $film ] then echo > /dev/null else if [ $film = 'q' ] then exit fi if [ $film = 'ironman' ] then echo $film' is a good film!' exit 0; else echo 'this film is not good enough' fi fidone
35. until
#!/bin/bash# auth: xiluhua# date: 2017-01-15n1=$1 if [ -z $n1 ]then n1=1fi echo 'n1='$1 until test $[n1] -gt 2do echo $n1 let 'n1++'done
36. case (1)
#!/bin/bash# auth: xiluhua# date: 2017-01-15 while truedo read -p 'please enter a num:' n1 case $n1 in 1|2|3|4|5) echo 'u enter:'$n1 ;; *) echo 'game over!' break esacdone
37. case (2)
#!/bin/bash# auth: xiluhua# date: 2017-01-15 while truedo read -p 'please enter a num:' n1 case $n1 in 1|2|3|4|5) echo 'u enter:'$n1 ;; *) continue esacdone
38. funtion
#!/bin/bash# auth: xiluhua# date: 2017-01-15 first(){ echo 'i am handsome!'} first 39. function 传参
#!/bin/bash# auth: xiluhua# date: 2017-01-15 second(){ echo 'first args:'$1 echo 'second args:'$2} second 1 2 40. 重定向
标准输入文件(stdin)：stdin的文件描述符为0，Unix程序默认从stdin读取数据。标准输出文件(stdout)：stdout 的文件描述符为1，Unix程序默认向stdout输出数据。标准错误文件(stderr)：stderr的文件描述符为2，Unix程序会向stderr流中写入错误信息。
41. 输出错误重定向
xiluhua@localhost ~/t2scripts $ cat echo 2>>err.logxiluhua@localhost ~/t2scripts $ less err.log cat: echo: No such file or directory
42. 2&>1
find /etc -name passwd 2>&1 | less > e.log
43. 将标准输出重定向到一个文件的同时并在屏幕上显示
格式：2>&1 | tee xiluhua@localhost ~/t2scripts $ id das 2>&1 |tee logfileid: das: No such userxiluhua@localhost ~/t2scripts $ less logfileid: das: No such userlogfile (END)
44. Here Document
xiluhua@localhost ~/t2scripts $ wc -l << EOF> 1> 2> 3> EOF3
45. function 引用
#!/bin/bash# auth: xiluhua# date: 2017-01-15 . ./t21.sh second 3 4
46. 为变量设定默认值
[ -z "$name" ] && name="obama"
47. 测试脚本语法
bash -n scripts.sh
48. 1加到100
#!/bin/bash# auth: xiluhua# date: 2017-03-19declare -i sum=0 for i in { 1..100};do sum=$[$sum+$i] if [ $i -eq 100 ];then echo $sum fi done