Script Editor $random and Case statements (notes) to be continued

$RANDOM

A personal understanding is a variable used to generate a random number, thus writing a script

[email protected] script]# cat random.sh

#!/bin/bash

#

Declare-i max=0

Declare-i min=0

For I in ' seq 1 10 '; Do

Myrandom= $RANDOM

[$I-eq 1] && min= $RANDOM

If [$I-le 9]; Then

Echo-n "$MYRANDOM,"

Else

echo "$MYRANDOM"

Fi

[$MYRANDOM-gt $MAX] && max= $MYRANDOM

[$MYRANDOM-lt $MIN] && min= $MYRANDOM

Done

Echo $MAX, $MIN

[Email protected] script]#

This script is used to compare the number of random numbers generated to a maximum and minimum number and display

Script Execution Results:

[Email protected] script]# bash random.sh

20744,24195,5854,24168,10197,16685,10095,27664,14198,22593

27664, 5854

[Email protected] script]#

Programming is divided into two categories

Process oriented

Control structure

Sequential structure

Select structure

Loop structure

Object oriented

Select structure

If statement: Single branch, dual branch, multi-branch

Now a new choice structure case

Use formatting

Case $ in

value1)

Statement

...

;; (Note that you must add a double semicolon)

value2)

Statement

...

;;

VALUE3)

Statement

...

;;

Esac

Here's a simple script when the user follows a parameter to identify whether it's a number or an uppercase or lowercase letter, or a special character

[email protected] script]# cat recognition.sh

#!/bin/bash

#

Case $ in

[0-9])

echo "a number";;

[[: Upper:]])

echo "Upper";;

[[: Lower:]])

echo "a lower case";;

*)

echo "special character";;

Esac

[Email protected] script]#

Execution Result:

[Email protected] script]#/recognition.sh 2

A number

[Email protected] script]#./recognition.sh E

Upper

[Email protected] script]#./recognition.sh E

A lower case

[[email protected] script]#./recognition.sh #

Special character

[Email protected] script]#

Of course I this only support single-character, later study advanced again practice, here only do a brief introduction!! Oo

Not to be continued

Script Editor $random and Case statements (notes) to be continued