tty

Print the terminal device name

$ tty

$ tty -s

$ if tty -s; then echo "Interactive"; fi

$ tty --version

tty [options]

tty prints the file name of the terminal connected to standard input. The output is typically a device path like /dev/pts/0 (pseudo-terminal) or /dev/tty1 (virtual console).
If standard input is not connected to a terminal (e.g., when input is piped or redirected from a file), tty prints "not a tty" and exits with status 1.
The -s option suppresses output entirely, making it useful in scripts where only the exit status matters. This allows testing whether a script is running interactively or in a batch/piped context.

-s, --silent, --quiet

Print nothing; only return exit status

Display help and exit

Output version information and exit

Check if running interactively

$ if tty -s; then
    echo "Running in terminal"
else
    echo "Running non-interactively"
fi

$ MYTERM=$(tty)
echo "Connected to: $MYTERM"

0

Standard input is a terminal

Standard input is not a terminal

Invalid option specified

The tty command only checks standard input. If stdin is redirected but stdout/stderr are still connected to a terminal, tty will report "not a tty". For more detailed terminal checks, consider using test -t or examining /proc/self/fd/.

The tty command dates back to the earliest versions of Unix at Bell Labs in the 1970s. The name comes from "teletypewriter," the original terminal devices. The GNU coreutils version was written by David MacKenzie. The command is specified in POSIX.

stty(1), who(1), mesg(1), write(1)