internal and external commands in linux shell

There are 2 types of Linux Commands.
  • Internal (Shell Built ins)
  • External
Internal commands are better than external commands from performance point of view as shell does not have to fork new process to run internal commands (also called as built-ins). You can find out if specific command is internal or external by executing below command.
 
$type <command-name>

If you get the output as command is “shell built-in”, that means the command is internal otherwise it is external. Here are the examples of Internal Commands
 
cd
echo
pwd

Here are the examples of External Commands
 
ls
dir

Complex problems, Simple Solutions