Grabing the username

Hi,
Is there a way to grab the username who is running the shell script. I am trying to do is:

$ who am i
Peterd123 pts/5 Mar 20 09:30 (H0021563.xyz.com)

Is there a way to display only the user name above, which is"Peterd123".

Thanks
Raj

echo ${USER}
who am i | nawk '{print $1}'

Thanks a bunch....it worked for me...

i would go for just,

whoami