shell编程语法

if

#!/bin/bash port=$(nmap -sT 127.0.0.1 |grep tcp |grep mysql |awk '{print $2}') if [ "$port" == "open" ] then echo "$(date) mysql is ok !" else /etc/init.d/mysqld restart &> /dev/null echo "wrong" fi

case

#!/bin/bash echo "you want to shanghai.please input 1" read -t 30 -p "choise:" cho case "$cho" in "1") echo "shanghai ready" ;; "2") echo "beijing ready" ;; esac

for

#!/bin/bash for i in 1 2 3 4 5 do echo $i done cd /home/hzhw/sh ls *.sh > ls.log y=1 for i in $(cat ls.log) do echo $y y=$(($y+1)) done s=0 for(( i=1;i<=10;i=i+1 )) do s=$(($s+$i)) done echo "$s"

while until until与while相反

#!/bin/bash i=0 s=0 while [ "$i" -le 100 ] do s=$(($s+$i)) i=$(($i+1)) done echo "$s" #!/bin/bash i=0 s=0 until [ "$i" -gt 100 ] do s=$(($s+$i)) i=$(($i+1)) done echo "$s"