标签：not found ted exit conf 模式 style 缩进 help and
适合判断变量值
case 变量引用 in
PAT1/值1)
分支1/指令1
;;
PAT2/值2)
分支2/指令2
;;
...
*)
默认分支
;;
esac
*: 任意长度任意字符
?: 任意单个字符
[ ]：指定范围内的任意单个字符
a|b: a或b
注意变量引用就是带$变量的名称。
如果第1个模式不匹配就继续执行第2个模式的代码。
*相当于else操作，表示的任意的字符串。
满足*就执行默认分支的操作。默认分支后面的两个分号可以不写的。
[root@centos7 ~]# type case
case is a shell keyword
[root@centos7 ~]# help case
case: case WORD in [PATTERN [| PATTERN]...) COMMANDS ;;]... esac
Execute commands based on pattern matching.
Selectively execute COMMANDS based upon WORD matching PATTERN. The
`|‘ is used to separate multiple patterns.也就是表示或的关系
Exit Status:
Returns the status of the last command executed.
使用case写脚本判断变量是否是离散值
如果变量num的值是1，2，3那么就执行某个命令cmd1。
如果变量num的值是4，5，6那么就执行某个命令cmd2。
如果变量num的值是7，8，9那么就执行某个命令cmd3
否则就执行其他命令
[root@centos73 shell_scripts]# cat case_1.sh
#!/bin/bash
#Author=wang
case $num in
1|2|3)
echo 1,2,3
;;
4|5|6)
echo 4,5,6
;;
7|8|9)
echo 7,8,9
;;
*)
echo other
esac
没有对变量num赋值，所有都显示其他
[root@centos73 shell_scripts]# bash case_1.sh 4
other
[root@centos73 shell_scripts]# bash case_1.sh 46
other
[root@centos73 shell_scripts]# bash case_1.sh 1
other
[root@centos73 shell_scripts]# bash case_1.sh 5
other
[root@centos73 shell_scripts]# bash case_1.sh 7
other
[root@centos73 shell_scripts]# bash case_1.sh 9
other
[root@centos73 shell_scripts]#
完整脚本
[root@centos73 shell_scripts]# cat case_1.sh
#!/bin/bash
#Author=wang
read -p "please input a num: " num
case $num in
1|2|3)
echo 1,2,3
;;
4|5|6)
echo 4,5,6
;;
7|8|9)
echo 7,8,9
;;
*)
echo other
esac
执行结果
[root@centos73 shell_scripts]# bash case_1.sh
please input a num: 1
1,2,3
[root@centos73 shell_scripts]# bash case_1.sh
please input a num: 3
1,2,3
[root@centos73 shell_scripts]# bash case_1.sh
please input a num: 5
4,5,6
[root@centos73 shell_scripts]# bash case_1.sh
please input a num: 7
7,8,9
[root@centos73 shell_scripts]# bash case_1.sh
please input a num: 9
7,8,9
[root@centos73 shell_scripts]# bash case_1.sh
please input a num: 11
other
判断yes或no
完整脚本
[root@centos73 shell_scripts]# cat yesorno_case.sh
#!/bin/bash
#Author=wang
read -p "Do you agree?(yes or no): " ans
case $ans in
[Yy]|[Yy][Ee][Ss])
echo yes
;;
[Nn]|[Nn][Oo])
echo no
;;
*)
echo other
esac
执行结果
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): Y
yes
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): y
yes
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): N
no
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): n
no
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): yes
yes
[root@centos73 shell_scripts]# Yes
-bash: Yes: command not found
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): Yes
yes
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): YeS
yes
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): YEs
yes
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): yEs
yes
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): yES
yes
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): yeS
yes
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): no
no
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): No
no
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): NO
no
[root@centos73 shell_scripts]# bash yesorno_case.sh
Do you agree?(yes or no): nO
no
使用正则表达式判断yes或no
（）表示和前面的分开，进行分组
而前面中括号里面的[Yy]是一定有的
？在正则表达式里面表示匹配其前面的字符0 或1次，也就是前面字符可有可无
[root@centos73 ~]# ans=yes;[[ $ans =~ ^[Yy]([Ee][Ss])?$ ]] && echo yes
yes
[root@centos73 ~]# ans=Yes;[[ $ans =~ ^[Yy]([Ee][Ss])?$ ]] && echo yes
yes
[root@centos73 ~]# ans=YEs;[[ $ans =~ ^[Yy]([Ee][Ss])?$ ]] && echo yes
yes
[root@centos73 ~]# ans=YES;[[ $ans =~ ^[Yy]([Ee][Ss])?$ ]] && echo yes
yes
[root@centos73 ~]# ans=YEs;[[ $ans =~ ^[Yy]([Ee][Ss])?$ ]] && echo yes
yes
[root@centos73 ~]# ans=yEs;[[ $ans =~ ^[Yy]([Ee][Ss])?$ ]] && echo yes
yes
[root@centos73 ~]# ans=Y;[[ $ans =~ ^[Yy]([Ee][Ss])?$ ]] && echo yes
yes
[root@centos73 ~]# ans=y;[[ $ans =~ ^[Yy]([Ee][Ss])?$ ]] && echo yes
yes
[root@centos73 ~]# ans=N;[[ $ans =~ ^[Nn]([Oo])?$ ]] && echo no
no
[root@centos73 ~]# ans=n;[[ $ans =~ ^[Nn]([Oo])?$ ]] && echo no
no
[root@centos73 ~]# ans=no;[[ $ans =~ ^[Nn]([Oo])?$ ]] && echo no
no
[root@centos73 ~]# ans=No;[[ $ans =~ ^[Nn]([Oo])?$ ]] && echo no
no
[root@centos73 ~]# ans=NO;[[ $ans =~ ^[Nn]([Oo])?$ ]] && echo no
no
[root@centos73 ~]# ans=nO;[[ $ans =~ ^[Nn]([Oo])?$ ]] && echo no
no
完整脚本
[root@centos73 shell_scripts]# cat yesorno_if.sh
#!/bin/bash
#Author=wang
read -p "do you agree (yes/no):" choice
yes="^[Yy]([Ee][Ss])?$"
#（）表示和前面的分开，进行分组
no="^[Nn]([Oo])?$"
if [[ "$choice" =~ $yes ]] ; then
echo "you enter yes"
elif [[ "$choice" =~ $no ]] ; then
echo "you enter no "
else
echo "enter not a yes or no "
fi
执行结果
[root@centos73 shell_scripts]# bash yesorno_if.sh
do you agree (yes/no):yes
you enter yes
[root@centos73 shell_scripts]# bash yesorno_if.sh
do you agree (yes/no):Y
you enter yes
[root@centos73 shell_scripts]# bash yesorno_if.sh
do you agree (yes/no):y
you enter yes
[root@centos73 shell_scripts]# bash yesorno_if.sh
do you agree (yes/no):N
you enter no
[root@centos73 shell_scripts]# bash yesorno_if.sh
do you agree (yes/no):n
you enter no
[root@centos73 shell_scripts]# bash yesorno_if.sh
do you agree (yes/no):nO
you enter no
[root@centos73 shell_scripts]# bash yesorno_if.sh
do you agree (yes/no):YeS
you enter yes
[root@centos73 shell_scripts]#
系统自带的函数是多层嵌套，尽量不要使用嵌套，否则就是给自己挖坑
[root@centos6 ~]# declare -f | less
if [ "true" = "$(git rev-parse --is-inside-git-dir 2>/dev/null)" ]; then
if [ "true" = "$(git rev-parse --is-bare-repository 2>/dev/null)" ]; then
c="BARE:";
else
b="GIT_DIR!";
fi;
else
if [ "true" = "$(git rev-parse --is-inside-work-tree 2>/dev/null)" ]; then
if [ -n "${GIT_PS1_SHOWDIRTYSTATE-}" ]; then
if [ "$(git config --bool bash.showDirtyState)" != "false" ]; then
git diff --no-ext-diff --quiet --exit-code || w="*";
if git rev-parse --quiet --verify HEAD > /dev/null; then
git diff-index --cached --quiet HEAD -- || i="+";
else
i="#";
fi;
fi;
fi;
标签：not found ted exit conf 模式 style 缩进 help and
原文地址：https://www.cnblogs.com/wang618/p/11087540.html
