Shell programming for loops __HTML5 under Linux

Linux for loops can use break and continue keywords to jump out of loops, consistent with Java usage

a common for loop structure

#语法一 for
variable in value 1 value 2 value 3.
   Do
     program block done

# #语法二 The for
variable ' command '
   do
     program block

# #语法三 for
(initial value; Cycle control; Variable) do
    program block done
  

Two common test structure

1. Output 3 times uptime

#!/bin/bash for

i in 1 2 3 4 5 
does
echo "$i-->$ (uptime)"
done

2. Bulk extract all the. tar.gz files under the current folder

#!/bin/bash for

i in ' ls/*.tar.gz ' doing  
     tar-zxvf $i >/dev/null
   Done

3. To seek 1~100 and

#!/bin/bash

#注意变量赋值的时候, = must not have spaces on either side
sum=0 for
((i=1; i<=100; i++)) do  
   sum=$ (($sum + $i))
  Done

echo "1+2+3+...+100= $sum"