System is how to identify the inside of the shell commands? Such as input CD, how do you know it is a command system?

CodePudding user response:

Determine whether it is a built-in command to use type, plus the -a can view the command in the path,

CodePudding user response:

Is not a system, it is the shell

You can use a type alias test alias is shell built-in commands, type is a built-in command

You input command shell will judge, look at whether alias, or variables/functions, or listed in the path environment variable path to find the feasible file (binary or shell script)

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