When the echo $LOGNAME and logname commands run normally, I get identical results from them:
pandya@pandya-desktop:~$ echo $LOGNAME
pandya
pandya@pandya-desktop:~$ logname
pandya
Is there any difference between them?
From Environment variables:
$LOGNAME is same as $USER which gives
The name of the currently logged-in user. This variable is set by the
system. You probably shouldn't change its value manually.
From man logname:
logname - print user´s login name
Explained differently used by following example:
pandya@pandya-desktop:~$ sudo su
root@pandya-desktop:/home/pandya# echo $LOGNAME
root
root@pandya-desktop:/home/pandya# logname
pandya
root@pandya-desktop:/home/pandya# exit
exit
pandya@pandya-desktop:~$
Here you can see the difference after logging as root in a terminal,
$LOGNAME gives the name of the currently logged-in user in the terminal (i.e root)logname prints the user's login name who logged in to the session (i.e. pandya)
