shell 自己常用的语法

替换字符

sed 's/:/ /g'  #把：换成空格
tr '\n' '#'    #把换行换成#

获取行数/字段数/字数

wc -w
wc -c
#        -c      Count bytes
#        -l      Count newlines
#        -w      Count words
#        -L      Print longest line length

判断

if [ $1 = "bind_key" ] && [ ! -z $2 ]; then 
	nvram set test1 bindkey $2
	nvram commit
	echo "set bind_key success"

elif [ $1 = "sn" ] && [ ! -z $2 ]; then
	nvram set test1 sn $2
	nvram commit
	echo "set sn success"
fi

循环

whitelist=`nvram get test1 whitelist | sed 's/#/ /g'`
for loop in $whitelist
do
	echo $loop | sed 's/,/ /g' >> /mnt/mtdblock7/aclwhite
done

while true
do
	checkbnt
	sleep 1
done

加法

cnt=0
if [ $cnt -gt 0 ]; then
    cnt=$(($cnt + 1))
fi

获取命令执行结果

res=`ifconfig eth0.2`
echo $res

函数调用

check_multi_network() {
	reb=`ifconfig br-ran | wc -l`
	if [ $reb -eq 0 ]; then
		uci set network.ran=interface
		uci set network.ran.ifname=eth0.3
		uci set network.ran.type=bridge
		uci set network.ran.proto=static
		uci set network.ran.ipaddr=192.168.2.1
		uci set network.ran.netmask=255.255.255.0
		uci commit
		/etc/init.d/network restart
	fi       
	iwpriv ra0 set CountryRegion=1
	iwpriv rai0 set CountryRegionABand=6
}

while true
do
	check_multi_network
	sleep 5
done

递归所有文件

#递归列出目录下的所有文件名（不包括目录），并且去掉空行

ls -lR |grep -v ^d|awk '{print $9}' |tr -s '\n'

去重

https://blog.csdn.net/laobai1015/article/details/91455406

 

大小写转换

tr '[a-z]' '[A-Z]' #小写转大写
tr '[A-Z]' '[a-z]' #大写转小写

生成软链接

ln -s /tmp/log.txt log.txt  #把tmp目录下的文件创建一个快捷方式到这里
ln -s /tmp tmp              #在当前目录下也能访问tmp文件夹