對Shell幾個冷知識的總結(IFS,數組,替換,分割,查找)
阿新 • • 發佈：2017-06-17
org pack sqlit com track 創建 gawk read 什麽
分割：
IFS:
對IFS的用處直接進行說明，詳細IFS是幹什麽的...自行谷歌
首先創建一個 "a a"，和"a"的文件:
然後我們 ls查看一下：
--> ls a a a是這種。
然後假如我們須要寫腳本操作每個文件：
--> for i in $(ls); do echo "$i" ;done a a a可是結果確實這種，顯然與我們的要求不符
由於IFS的值是空格，制表符。回車。所以這裏把a a變成了2個a
可是我們改動了IFS以後例如以下：
--> OldIfs=$IFS;IFS=$‘\n‘;for i in $(ls); do echo "$i" ;done ;IFS=$OldIfs a a a
數組：
一個腳本進行說明：
#!/bin/bash
# *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
# > Author: xiaojunyu/LunaW
# > Mail : [email protected]
# > Gmail : [email protected]
# > Blog : http://blog.csdn.net/lunaw
# > Web : http://lunaw.org http://lunaw.net
# *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
# DEPENDS:=+libsqlite3 +libcurl +libpthread +libc
# 默認選擇的包
SelectPackages=(
"sed"
"gawk"
"grep"
"bc"
"luci-lib-json"
"iperf"
"tc"
"restorefactory"
"xinetd"
"n2n"
)
# 默認不選擇的包 優先級強於選擇的包
UnSelectPackages=(
"horst"
"vim-full"
"vim-runtime"
"qos-scripts"
"wifidog"
"libcurl"
"curl"
"tc"
"sqlite3-cli"
"libsqlite3"
)
if [[ -f .config ]]; then
for Name in `seq 1 ${#SelectPackages[*]}`
do
PackageName="CONFIG_PACKAGE_${SelectPackages[$(expr $Name - 1)]}"
if [[ `cat .config| grep "${PackageName}=y"| wc -l` == 0 ]]; then
echo -e "\e[01;31mNot Found (${PackageName}=y) "
if [[ `cat .config| grep "# ${PackageName} is not set"| wc -l` == 1 ]]; then
echo -e "\e[01;33mFound (# ${PackageName} is not set) "
sed -i "s/# ${PackageName} is not set/${PackageName}=y/g" .config
echo -e "\e[01;36mReplace (${PackageName}=y) done!"
else
echo -e "\e[01;31mNot Found (# ${PackageName} is not set) "
echo "${PackageName}=y" >> .config
echo -e "\e[01;36mAdd (${PackageName}=y) done!"
fi
else
echo -e "\e[01;33mFound (${PackageName}=y) "
fi
done
echo "--------------------------------------"
for Name in `seq 1 ${#UnSelectPackages[*]}`
do
PackageName="CONFIG_PACKAGE_${UnSelectPackages[$(expr $Name - 1)]}"
if [[ `cat .config| grep "# ${PackageName} is not set"| wc -l` == 0 ]]; then
echo -e "\e[01;31mNot Found (# ${PackageName} is not set) "
if [[ `cat .config| grep "${PackageName}=y"| wc -l` == 1 ]]; then
echo -e "\e[01;33mFound (${PackageName}=y) "
sed -i "s/${PackageName}=y/# ${PackageName} is not set/g" .config
echo -e "\e[01;36mReplace (# ${PackageName} is not set) done!"
else
echo -e "\e[01;31mNot Found (${PackageName}=y) "
echo "# ${PackageName} is not set" >> .config
echo -e "\e[01;36mAdd (# ${PackageName} is not set) done!"
fi
else
echo -e "\e[01;33mFound (# ${PackageName} is not set) "
fi
done
else
echo -e "\e[01;31mNot Found .config"
fi
echo -e "\e[01;00m+---------------------------------+"
echo -e "\e[01;00m| 不用操心，這僅僅是選擇了幾個包! |"
echo -e "\e[01;00m+---------------------------------+"
sleep 1
替換：
單一替換
--> XiaoName="xiaojunyu"; echo "${XiaoName/x/j}"
jiaojunyu所有替換--> XiaoName="xiaojunyu"; echo "${XiaoName//u/a}"
xiaojanya
刪除
--> XiaoName="xiaojunyu"; echo "${XiaoName//u/}"
xiaojny分割：
有幾種方法。第一種：
XiaoCh="xiao;jun;yu"
for i in ${XiaoCh//;/ }
do
echo "$i"
done xiao jun yu可是假如是這種話：
XiaoCh="xiao;j un;yu"
for i in ${XiaoCh//;/ }
do
echo "$i"
done 輸出：
xiao j un yu並非我們預料的那樣。然後另外一種切割方法
IFS法：
XiaoCh="xiao;j un;yu"
OldIFS=$IFS
IFS=$‘;‘
XiaoArr=($XiaoCh)
for i in ${XiaoArr[@]}
do
echo "$i"
done
IFS=$OldIFS輸出：xiao j un yu
查找：
查找一個字符串是否包括還有一個字符串
--> XiaoA="abc"; XiaoB="a"; [[ "${XiaoA/${XiaoB}/}" == "$XiaoA" ]] && echo "No" || echo "Yes"
Yes
--> XiaoA="abc"; XiaoB="w"; [[ "${XiaoA/${XiaoB}/}" == "$XiaoA" ]] && echo "No" || echo "Yes"
No
對Shell幾個冷知識的總結(IFS,數組,替換,分割,查找)