Shell script-Conditional statement, loop statement

Conditional statements

1#!/bin/Bash2 3Read-p"input your name:"name4 #第一种判断5 if["$name"=="Mike" ];then #注意这里用 [...] When comparing two strings, the variable $name  quoted, and there are spaces on both sides of "= ="; "[" followed by a space; "]" preceded by a space 6     Echo "eq"7 Else8     Echo "Not eq"9 fiTen  A#The second kind of judgment - ifTest$name="Mike";Then #注意这里用 Test compares two strings, the variable $name is not quoted , and "=" has spaces on both sides -     Echo "eq" the Else  -     Echo "Not eq" - fi

The first judgment and the second is equivalent.

Case statement

1#!/bin/Bash2 3Read-p"input your name:"name4 5  Case$nameinch 6     "Mike" )7         Echo "You are Mike"8      ;;9     "Tom" )Ten         Echo "You are Tom" One     ;; A*) #相当于通配符, 0~ Infinite number of arbitrary characters -         Echo "anything" -     ;; the Esac

Cycle

1  while[Condition] #表示condition成立时, execute2  Do3 #程序段落4  Done5 6 7 until[condition] #表示condition不成立时, execution, or, if established, exit the loop8  Do9 #程序段落Ten  Done One  A  -  forVarinchcon1 con2 con3 ... # first cycle, $var content is con1; second time is con2 .... -  Do the #程序段落 -  Done -  -  +  for((i=1; i< -; i=i+1)) -  Do +s=$ (($s +Si)) A  Done

Shell script-Conditional statement, loop statement