rmux

A drop-in replacement for tmux written in Rust.

Wire-compatible with tmux's imsg protocol (v8) — real tmux clients can connect to an rmux server and vice versa. CLI flags, key bindings, and config syntax match tmux.

Install

cargo install --path crates/rmux-client
cargo install --path crates/rmux-server

Usage

rmux                        # Start a new session (auto-starts server)
rmux new-session -s work    # Named session
rmux attach                 # Reattach to existing session
rmux ls                     # List sessions

Key bindings work like tmux: Ctrl-b is the prefix key.

Keys	Action
`Ctrl-b c`	New window
`Ctrl-b n` / `p`	Next / previous window
`Ctrl-b 0-9`	Select window by number
`Ctrl-b d`	Detach
`Ctrl-b "` / `%`	Split pane horizontal / vertical
`Ctrl-b o`	Cycle panes
`Ctrl-b x`	Kill pane
`Ctrl-b :`	Command prompt
`Ctrl-b [`	Copy mode
`Ctrl-b ]`	Paste buffer

Build

cargo build                                        # Debug build
cargo build --release                              # Release build
cargo test                                         # Run all tests
cargo clippy --all-targets --all-features          # Lint
cargo bench -p rmux-core                           # Benchmarks
make check                                         # Format + lint + test
make e2e                                           # E2E tests (requires tmux)
make fuzz                                          # Fuzz all targets (requires nightly)

Architecture

rmux-core       Pure data structures (Grid, Screen, Style, Layout, Options)
rmux-terminal   VT100 parser, PTY operations, escape sequence generation
rmux-protocol   imsg wire protocol, message encode/decode
rmux-server     Async event loop, session/window/pane management
rmux-client     CLI, server auto-start, attached mode I/O

Client and server communicate over a Unix domain socket at $TMPDIR/rmux-$UID/default.

Testing

Unit and integration tests run via cargo test. Command integration tests use a MockCommandServer to verify behavior without I/O. Property-based tests use proptest for data structure invariants.

E2E tests (make e2e) launch rmux inside a real tmux session and exercise the full stack — pane splitting, copy mode, window management, non-attached client commands, detach/reattach, and more.

Fuzz targets (make fuzz) cover all parsers and data ingestion points.

License

ISC

TrevorS/rmux

README