whoami(1)

The whoami command prints the login name of the current effective user. It is equivalent to id -un and reads the UID from the environment or system calls, then translates it to a username.

This is useful in scripts, shell prompts, and for quickly confirming your identity when logged in, especially over remote sessions or after using su or sudo.

Display the current logged-in user's username

whoami

Show that you are root when running a command with sudo

sudo whoami

Use whoami in a conditional to check if the script is running as root

if [ "$(whoami)" = "root" ]; then echo "Running as root"; fi

Log the current username to a file using command substitution

echo "User: $(whoami)" >> logfile.txt