ptypipe

ptypipe is a small command-line utility that runs its first argument in a pseudo terminal created with forkpty(). This is handy for the following cases:

• Undoing glibc's behavior of buffering stdin/stdout, which makes pipe-based wrapped command shells useless.

• Using a different window size for programs than the controlling TTY.

• Notifying a pipe-based wrapped shell that the window size has changed.

One can get a similar result to this program through other means. The 'script' utility supplied in most POSIX-like systems can emulate a TTY. 'pipetty' (licensed GPL) is also available from the KBtin source.

Usage

ptypipe { command } { arguments }

Resizable Window Support

ptypipe monitors its stdin for the dtterm/xterm sequence:

ESC [ 8 ; { rows } ; { cols } t

If this sequence is seen, it is stripped from the input to the child process and ioctl(TIOCSWINSZ) is executed to notify the child of a new window size. One could thus do something like:

/bin/echo -ne "\033[8;20;40t" | ptypipe ls

...and ls will execute with a window size of 20 rows by 40 columns.

Jexer illustrates how ptypipe can work for a larger program. Jexer is 100% Java, but needs to spawn interactive terminals. It can do this with either 'script' or 'ptypipe'. Using 'script' results in terminal windows that cannot be resized; using 'ptypipe' those terminal windows resize as expected in modern programs.

License

ptypipe is licensed under the MIT License. See the file LICENSE for the full license text.

Bugs

If an ESC is in the stream ahead of a correct resize sequence, the resize sequence is not noticed and will be emitted to the child process.