Linux Shell 01 Scripts and variables

Creation and execution of a script

1. Create file *.sh, file suffix sh

2. Editing scripts

The first line must be: #!/bin/bash #指定解释脚本的shell

3. Empowering

chmod u+x a.sh

4. Implementation

./a.sh

Variables in the two shell scripts

1. Definition and deletion of variables

Name= "Hello" #定义变量 = cannot have spaces before and after

unset name #删除变量

A. Variables defined in the current shell are valid only in the current shell

B. Whether it is a normal variable or an environment variable, in the final analysis is a variable, all follow the basic operation of the variable

2. Environment variables

(1) View all environment variables: set/env

(2) To view the environment variables associated with the specified process

Pgrep Process_name #获取应用程序的进程号

Cat/proc/process_num/environ #根据进程号获取相关环境变量

(3) Increase and modification of environment variables

Introduction to environment variables

Http://www.cnblogs.com/techroad4ca/p/5068549.html

3. References to variables

Add $ symbol To reference variable value before variable

Cases:

Echo $USER

Name=hello

echo $name # "Hello"

N1=name

N2= $name

echo N1 n2 # "name" "Hello"

Linux Shell 01 Scripts and variables