Shell Loop statement

One, for-done (not very common)

1. Grammar

For variable in name table do    ... done

2. Script Sample Code

#!/bin/shfor num in 1 2 3 4 5do    echo "number is $num" done

3. Execute script

[Email protected]]# sh hello.sh

4. Implementation results

The number is 1 the number is 2 the number is 3 the number is 4 the number is 5

Second, select (Not very common)

1. Grammar

Select variable in list do    ... done

2. Script Sample Code

#!/bin/shselect fruit in "apple" "Pear" "peach"    do Breakdoneecho "you chose $fruit"

3. Implementation results

1) Apple 2) Pear 3) Peach #? 1   //This place requires you to input your choice is Apple

Third, case

1. Grammar

Case variable in    string 1)    command list 1;;    String 2)    command List 2;;    *)    Command list 3esac

2. Script Sample Code

#!/bin/shread opcase $op    in a)    echo "you selected a";;    b)    echo "you selected B";;    *)    echo "Error" Esac

Four, while

1. Grammar

While [condition] //Note space do    ... done

2. Script Sample Code

#!/bin/shnum=1while [$num-le]do   num= ' expr $num + 1 ' doneecho $num

Shell Loop statement