Shell Foundation (i): Shell basic Application, simple shell script design, using shell variables, variable extension application

First, Shell basic application

Target:

This case requires familiarity with the characteristics of the Linux shell environment, mainly practicing the following actions:

1> switching the user's shell environment
2> Practice Command History, command aliases
3> REDIRECT standard input/output/error Output
4> Pipeline Operation Practice

steps:

Step one: Switch the user's shell environment

If you need to temporarily use another shell environment, you can directly execute the corresponding Shell interpreter program, such as simply executing ksh can switch to the KSH command-line environment.

[[email protected] ~]# yum-y Install Ksh//If missing Ksh Please install Ksh package first
.. ..
[Email protected] ~]# Cat/etc/shells
/bin/sh
/bin/bash
/sbin/nologin
/bin/tcsh
/bin/csh
/bin/ksh//Confirm that the current system is recognized Ksh
[[email protected] ~]# ksh//Enter KSH environment
[[Email protected]]~# exit//Return to bash environment before switching

Shell Foundation (i): Shell basic Application, simple shell script design, using shell variables, variable extension application