Logname

In computer software, logname (stands for Login Name) is a program in Unix and Unix-like operating systems that prints the name of the user who is currently logged in on the terminal. It usually corresponds to the LOGNAME variable in the system-state environment (but this variable could have been modified).

History
The logname system call and command appeared for the first time in UNIX System III. The author of the version of  bundled in GNU coreutils is unknown. The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities.