The so called term used "command" is basically a binary file. If you try to read any of those files using any editor then you won't understand any thing as it is not human readable. These all commands are installed along with the relative packages with the installation of OS.
These binary files are mostly located in the below 4 locations
You can either manually use the find or locate command to look out for the command in the above mentioned locations or alternatively you can use the below most suitable commands for this purpose
# which <command_name>
# which cp alias cp='cp -i' /bin/cp # which useradd /usr/sbin/useradd
In case you get the below error# which samba
/usr/bin/which: no samba in (/usr/lib/qt-3.3/bin:/usr/local/sbin /usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin)
It means your PATH variable does not contains the path for samba command. In that case which will not help you find the location of the command.
So, you can use the below command for the same purpose
# whereis <command_name>
# whereis useradd useradd: /usr/sbin/useradd /usr/share/man/man8/useradd.8.gz
I hope the article was useful
How to set environment (PATH) variable permanently in Linux
How to mount windows share on linux