babysit
Wrap a command in a PTY and control it from another terminal. The command runs in the background under a worker that owns the PTY and records its output. From anywhere you can read the output, screenshot the screen, send input, wait for exit, or attach interactively.
Useful for scripts and coding agents that need to drive a command they didn't start.
$ babysit run -d --json -- make local-ci # {"id":"ab12"}
$ babysit log -s ab12 --tail 20
$ babysit screenshot -s ab12
$ babysit wait -s ab12
babysit -- make local-ci is the interactive shorthand. For scripting, use
run -d --json and capture the id.
How it works
The command runs under a background worker that owns the PTY, logs all output, and serves a Unix control socket. Your terminal is just attached to it, so you can detach, re-attach, and query from other terminals.
State lives in ~/.babysit/sessions/<id>/. Set $BABYSIT_DIR (absolute path) to
change the root. status, log, and screenshot work after the worker exits;
send, key, restart, and kill need it alive.
-s <id> selects a session; there is no "most recent" fallback. Inside the
wrapped command the id is exported as $BABYSIT_SESSION_ID.
Install
|
The install script drops a prebuilt binary in ~/.local/bin (override with
BABYSIT_INSTALL_DIR, pin with BABYSIT_VERSION). babysit upgrade
self-updates cargo/binary installs; Nix installs are managed by Nix.
Run without installing: nix run github:yusukeshib/babysit -- -- make local-ci.
Subcommands
| Command | Description |
|---|---|
run |
Wrap a command in a PTY (babysit -- <cmd> shorthand; -d detached; --json prints the id) |
list (ls) |
List sessions |
status |
Session state and exit code |
log |
Show output; --tail, --grep, --follow, --since |
screenshot (shot) |
Render the current screen; --format plain|ansi|json, --trim |
send |
Send text to stdin (-n no newline; --json) |
key |
Send named keys (Enter, Up, Esc, C-c, F1, …) |
expect |
Block until a regex appears (--screen matches the rendered TUI) |
wait-idle |
Block until output is quiet for --settle |
wait |
Block until exit, return the exit code |
resize |
Resize the terminal (COLSxROWS) |
flag / unflag |
Flag a session for attention / clear it |
restart |
Restart the command |
kill |
Terminate the command |
attach / detach |
Attach your terminal (detach: Ctrl-\ Ctrl-\) / detach others |
prune |
Delete finished or dead sessions |
upgrade |
Self-update |
config |
Shell completions: eval "$(babysit config zsh|bash)" |
Each command documents its own flags and gotchas: babysit help <command>.
babysit --help covers the model and the typical agent loop.
Build from source