shell條件判斷

shell條件判斷
1. if條件判斷if條件判斷： if [ 條件 ]; then do something fi 多個條件： && 代表AND || 代表OR 多重判斷： if [ 條件 ];then do something elif [ 條件2 ]; then //do something else //do someshing fi

#!/bin/bashread -p "Please input (Y/N) : " ynif [ "$yn" == "Y" ] || [ "$yn" == "y" ]; then     echo "Yes!"elif [ "$yn" == "N" ] || [ "$yn" == "n" ]; then     echo "No!"else    echo "Input Error"fiexit 0

查看運行結果

[work@www sh]$ sh hello.sh Please input (Y/N) : yYes![work@www sh]$ sh hello.sh Please input (Y/N) : lInput Error[work@www sh]$

2. case判斷如果if中判斷層級比較多，建議使用case， 否則嵌套太多，代碼易讀性變差。 case的文法 case $變數名稱 in “變數1”) do something ;; 每個結尾用兩個分號 “變數2”) do something ;; *) 最後一個*代表其他值 do something ;; esac 看下面例子：

#!/bin/bashcase $1 in    "one")        echo "One"        ;;    "two")        echo "Two"        ;;    *)        echo "Usage $0 (one|two)"        ;;esacexit 0

運行結果

[work@ww sh]$ sh hello.sh Usage hello.sh (one|two)[work@www sh]$ sh hello.sh oneOne[work@www sh]$

地址：http://blog.csdn.net/yonggang7/article/details/40480695