Shell Script Programming Circular Statement Learning notes _linux Shell

This blog is simple to look at the loop statements that Shell programming uses, including for loops, while loops, until loops, for behind and a variable, and then a collection that assigns things to this variable, each loop, like a foreach in Java. While loops and if use the same condition to judge, satisfies the condition execution statement, until and while opposite, does not satisfy the condition execution statement, is not very simple ah, below looks the code.

Copy Code code as follows:

#!/bin/sh
#for循环最基本的用法
for Var in "Hello" "Xiao Ta" "Welcome to Www.jb51.net"
Todo
Echo-n "$var"
Done
Echo
#通配符扩展
For Var in $ (LS *.sh)
Todo
echo "$var"
Done

#while循环, the following is the same condition as if
echo "Please input secret"
Read Secret
While ["$secret"!= "Xiao Ta"]
Todo
echo "Try Again"
Read Secret
Done

#until循环和while相反, the condition is false before execution
echo "Please input text"
Read text
Until ["$text" = "Xiao Ta"]
Todo
echo "Try Again"
Read text
Done

Exit 0