The variables of shell learning

A variable definition

1 explicitly defined variable=xxx no spaces

2 Read variable Reading

The following two lines of code are written, reading name and namefamily

Read-p "Please input your name:" Name

Read-p "Please input your whole name:" Name family

Run under

[Email protected] shell]#./var.sh

Please input your Name:liuliancao

Your name Is:liuliancao

Please input your Name:liu Liancao

Your name Is:liu Liancao

Please input your whole Name:liancao Liu

Your name is Liancao,your family is Liu

Please input your whole Name:liancao

Your name is Liancao,your family is

Please input your whole name:liancao l IU

Your name is Liancao,your family is L IU

The number of visible variables and the number of inputs, the allocation is exactly, if the number of variables, then the following variable is empty, the number of variables is less, then the oldest is the eldest (eat the most).

3 reading from a file

[[email protected] shell]# Read Message < TXT

[Email protected] shell]# echo $message

Hello,i Amliuliancao because it is text redirection, and TXT text lines have line breaks, so there is only one line at this time, if you want to continue to use the loop

[[email protected] shell]# while read message

> Do

> Echo $message

> Done < txt

Hello,i am Liuliancao

This is a test

4 command substitution

1 #!/bin/bash

2 #

Time= ' Date +%c '

3 echo "Now Time is $time"

Execution results

[Email protected] shell]#./com.sh

Now time is Sat 12:26:49 PM CST

5 Position parameters

Common with

$ full file name basename can take the basic name

The first variable content, and so on

[Email protected] All variables are stored in an array $* all variables, grouped into large strings

6 Deleting a variable

unset variable Name

The variables of shell learning