sudo apt-get install gnome-session

[daviddixit]

/usr/lib/lightdm:/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

[schragge]

As sudodus said, or that you simply made a typo when typing chown. You also can try

sudo /bin/chown -R master: /home/master

If you'll get an error message that ownership of some directories cannot be changed (presumably of .gvfs), ignore it. It's normal.
Then reboot.

Edit. Your $PATH looks OK. So probably that was a typo.

[sudodus]

/usr/lib/lightdm:/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

/usr/lib/lightdm:/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

or

/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

as I have?

[audiomick]

... or that you simply made a typo when typing chown.

I'm inclined to think this is likely. chown is so fundamental, it must be there...

[sudodus]

Anyway /bin is in your path, and chown should be there. Try

ls -l /bin/chown

[schragge]

Good call, sudodus! This may be the cause of GUI login failing, but chown should have worked nevertheless.

[daviddixit]

I tried /bin/echo $PATH and got

/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

I tried second code again and got: [sudo] password for master

I put in my password and it ignored it, I tried again and it said commande intouvable.

[audiomick]

I put in my password and it ignored it

You do know, don't you, that you don't see what you are typing when you enter your password at the password request in the command line environment?

You just type in your password and hit enter.

Sorry if you do already know this, but it does confuse some users.

[sudodus]

I tried /bin/echo $PATH and got

/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

I tried second code again and got: [sudo] password for master

I put in my password and it ignored it, I tried again and it said commande intouvable.

So the extra colon was a typing error.

Did you try this one yet?

ls -l /bin/chown

and if the file is found try this one

sudo /bin/chown master:master /home/master

if it is not found the package with chown must be reinstalled.

[Kopkins]

Try

sudo apt-get install coreutils_8.13-3ubuntu3_i386

If chown is somehow missing, this should reinstall it.

Then try again

sudo chown master:master /home/master