Do you know when you run the Linux / Unix command it could be Internal or External ? In this article, we will learn about Linux Internal and External command. For identifying and understand on command type, here we have article for you.
Linux/Unix has so many commands. If you know these commands, your Linux work will be much more easier and faster.
In this post we have tried to provide the difference between Internal and External command in a simple manner.
Difference Between Linux Internal And External Command
In Linux, generally commands are categorised into two types – Internal Command and External Command.
We have simplify the difference between the two types of command in given below table.
| Internal Command | External Command |
|---|---|
| Internal commands are shell built-in commands. | External commands are other than shell built-in command. |
| It doesn’t need to be set in PATH variable. | We have to set the PATH variable for External commands. |
| Do not require any process to spawn on execution. | It require process to be spawned when it get executed. |
| Example: cd, source, fg, echo | Example: ls,cat. |
How To Identify Internal Or External Command
In above section, we read about the difference between Internal and External Command. But as a user, how can we identify the command type.
For identifying the Internal and External command, we will use the command called type .
We have already written about type command in detail, you must be interested to read this post – “type command : display information about command type on Linux“
For a quick check, use this Syntax
type [argument] [command name]
For example, let’s check if cd command is Internal or External
user1@server01:~$ type cd cd is a shell builtin user1@server01:~$
The above output shows that cd command is Internal Command means Shell Built-in . Try the same type command to identify other commands.
What is builtin Linux/Unix command?
The builtin or shell builtin or Internal command , all have same meaning. The builtin commands are the command which are available in Shell by default.
How to check PATH variable value ?
To check the PATH variable value , run the command echo $PATH in current user shell means when you run the command in terminal it shows the PATH value for current login user in terminal.
Conclusion
In this article, we have described the difference between Linux/Unix Internal and External command. This article will help to enhance the knowledge on Linux Command Line system.
