tty

Additional Notes

tty prints the filename of the terminal connected to standard input. The name comes from the historical Teletypewriter. Output is typically something like /dev/pts/3 for a pseudo-terminal, /dev/tty1 for a physical console, or not a tty if standard input is not a terminal.

The exit status reflects whether the input is a terminal: 0 if it is, 1 if it is not. This makes it useful in scripts for detecting whether output is being piped or redirected.

Syntax

tty [options]

Parameters

• options: Flags that change how tty behaves.
• target: Optional file, device, interface, user, service, or command target when the command supports one.

Common Options

• -s, --silent, --quiet: Do not print anything; only set the exit status.

Examples

tty

Print the terminal device path, e.g. /dev/pts/2.

tty -s && echo "Terminal" || echo "Not a terminal"

Check whether input is a terminal without printing the path.

# In a script
if tty -s; then
    echo "Input is from a terminal"
else
    echo "Input is from a pipe or file"
fi

Practical Notes

• Use tty -s in scripts to determine if output should use colors or interactive prompts.
• The -s flag is useful for silent checks; the exit code tells you everything.
• Piped commands return not a tty: echo "test" | tty.
• SSH sessions allocate a pseudo-terminal: the path will be e.g. /dev/pts/0.