TTY

Definitions

1. Short for teletypewriter, a TTY is a terminal device interface in Unix-like systems that provides line-buffered, character-oriented I/O between a user and the kernel. In modern usage, it refers to pseudo-terminal devices (/dev/pts/*) that terminal emulators and SSH sessions use, and programs check `isatty()` to decide whether to use color output, interactive prompts, or raw binary.

   In plain English: A terminal connection that programs can detect to decide whether they're talking to a human at a keyboard or to a pipe or file.

   Example: "The CI logs have no color because stdout isn't a TTY — pipe it through `script` or set FORCE_COLOR=1."

Related Terms

• Async
• Redirection
• Stdin/Stdout/Stderr
• Shell
• Standard Output
• Stderr
• Stdin
• Stdout