A GNU screen
style terminal multiplexer built on
libghostty
(libghostty-vt
), written in Zig.
Every session's output is parsed through Ghostty's terminal emulation core, so boo always knows the exact screen state of every session: contents, styles, cursor, scrollback, and terminal modes. That state is used to rehydrate your terminal on attach, to answer terminal queries for detached sessions, and to let scripts and AI agents read the screen exactly as a human would see it.
- Sessions that survive disconnects: detach with
Ctrl-A d
, reattach withboo attach
. - A full-screen session manager:
boo ui
lists sessions in a sidebar. - Faithful redraws from libghostty terminal state, including SGR styles, cursor position, scrolling regions, window title, and terminal modes.
- Agent-friendly automation primitives:
send
,peek
,wait
, and--json
output, all usable without a TTY.
demo.mp4 #
For Linux and macOS:
curl -fsSL https://raw.githubusercontent.com/coder/boo/main/install.sh | sh
Pre-built binaries are published on the releases page. Set BOO_VERSION
to pin a release and BOO_INSTALL_DIR
to change the
install location (default: /usr/local/bin
when writable, otherwise
~/.local/bin
).
boo new # new session running $SHELL, attached
boo new work # named session
boo new work -d -- make # create detached, running a command
boo ui # manage sessions in a full-screen UI (alias: i)
boo ls # list sessions
boo attach work # reattach (alias: at, a)
boo rename work api # rename a session
boo kill work # end a session
boo kill --all # end every session
With no name, boo new
names the session after the current directory, falling back to the process id when that name is taken or unusable.
Run boo help
for the full overview, boo help <command>
for flags
and examples, and boo help --all
to print every help page at once.
Bindings follow GNU screen's defaults, including the C-x
variants
(C-a C-d
detaches just like C-a d
).
| Keys | Action |
|---|---|
C-a d , C-a C-d |
|
| detach | |
C-a l , C-a C-l |
|
| redraw | |
C-a a |
|
send a literal C-a |
boo ui
adds additional keybinds for switching, resizing, creating sessions, and killing them.
Everything except attach
works without a terminal, which makes boo a natural sandbox for scripts and AI agents driving interactive programs. The canonical loop:
boo new build -d -- bash # 1. headless session
boo send build --text 'make' --enter # 2. type into it
boo wait build --idle # 3. let output settle
boo peek build --scrollback # 4. read the screen
boo kill build # 5. clean up
Reading state:peek
prints the rendered screen reconstructed from terminal state, not a raw byte log: ordered, fully redrawn, and stable.--scrollback
includes history;--json
adds size, cursor, and title.Waiting:wait --text <text>
blocks until the screen contains the text;wait --idle
until output has been quiet for 2 seconds;--timeout <dur>
exits 4 instead of hanging forever (durations:500ms
,2s
,1m
,4h
,1d
). No more sleep-and-poll loops.Sending input:send --text
is literal: no escape processing, no implicit newline, no quoting layer to fight.--enter
submits,--key Enter,C-c,Up
names control keys, and stdin mode is binary safe.Machine-readable output:ls --json
andpeek --json
.Exit codes:0
success,1
error,2
usage error,3
no such session,4
wait timed out.
See boo help automation
for the full page.
Requires Zig 0.15.2.
zig build # binary in zig-out/bin/boo
zig build test # unit tests
zig build test-integration # end-to-end tests on a real PTY
zig build test-all # everything
The libghostty dependency is fetched and built from source
automatically (pinned in build.zig.zon
).
With Nix, nix develop
opens a shell with the right Zig version, and
nix build
builds the package to ./result/bin/boo
.
your terminal <-(raw tty)-> boo client <-(unix socket)-> session daemon
`- PTY + ghostty-vt Terminal
- The
client puts your TTY in raw mode and shuttles bytes over a framed Unix-socket protocol (
src/protocol.zig
). - The
daemon(forked on session creation) owns the session's command: a PTY-attached child whose output feeds a persistentghostty-vt
TerminalStream
(src/window.zig
). - While attached, output is passed through to your terminal byte for
byte. On attach the daemon sanitizes your terminal and replays the
screen from libghostty state using its VT
TerminalFormatter
. - Terminal queries (DSR, DA, XTWINOPS, ...) while detached are answered by libghostty's stream handler; while attached your real terminal answers, avoiding double replies.
This is a young project, not a drop-in GNU screen replacement:
- One attached client per session (attaching steals); no
-x
sharing. - One window per session: no splits or tabs inside a session. Run one
session per task and juggle them with
boo ui
. - The
C-a
prefix is not yet configurable, and pasted bytes containing0x01
are interpreted as the prefix (GNU screen has the same quirk;boo ui
is immune thanks to bracketed paste). - Sessions run with
TERM=xterm-256color
.
Feel free to open an issue if you have questions, run into bugs, or have a feature request.
MIT. Ghostty itself is MIT licensed.