01-shell Basic Overview

• The shell is a command interpreter
• Shell scripts are similar to batch programs under a DOS system (disk operating system)
• The Shell scripting language is ideal for working with plain text types of data (configuration files, log files)
• The Shell scripting language is a weakly typed language (it is not necessary to define the type of the variable)

Type of shell

[[email protected] ~]# cat /etc/shells/bin/sh         # 指向/bin/bash，sh为bash的软连接/bin/bash       # 默认的使用的shell/sbin/nologin   # 用于禁止用户登录/bin/dash/bin/tcsh/bin/csh

How the script executes:

bash test.sh    # 无需修改权限sh test.sh      # 无需修改权限./test.sh       # 需要修改执行权限chmod +x test.shsource test.sh  # 相当于PHP的includesh<test.shcat test.sh|sh

01-shell Basic Overview