Thread: Find Out If Linux Command Is Internal Or External

Hi I m new to Linux and looking for answer of my question here.
As per my understanding Internal commands are those which are built-in, and external are those which are stored somewhere in binary files as executables.
But how to understand whether a command is internal or external. Like cat, date, cp , echo etc.

Simply use type command:

Code:

type -a bash

bash is /bin/bash

Code:

type -a cp

cp is /bin/cp

Code:

type -a echo

echo is a shell builtin
echo is /bin/echo

Code:

type -a ls

ls is aliased to `ls --color=tty'
ls is /bin/ls

How Linux or UNIX Understand which program to run - PART I

Thanks Monk for the quick reply.It was really useful.