TIL

Check for TTY Before Running stty Commands

Commands like stty that modify terminal settings fail in non-interactive contexts (shell spawning, piped commands, scripts). Always check if stdin is a TTY first:

# BAD: Fails when shell is spawned non-interactively
stty -ixon

# GOOD: Only runs when stdin is a TTY
if [[ -t 0 ]]; then
  stty -ixon  # Disable flow control
fi

The [[ -t 0 ]] test checks if file descriptor 0 (stdin) is connected to a terminal.

Common stty settings that need this guard:

• stty -ixon - Disable Ctrl+S/Ctrl+Q flow control
• stty erase ^? - Set backspace behavior
• stty susp undef - Disable Ctrl+Z suspend