notMyShell

A focused frontend over your persistent zsh, Bash, and Fish sessions. NMSh owns what you see and type—providing a docked or flowing composer, background semantic classification, a searchable transcript, live command telemetry, and clean shell handoff.

Getting Started Architecture GitHub Repository

The Terminal Frontend Experience

notMyShell is not a shell, not a terminal emulator, and not an AI assistant. It orchestrates a hidden pseudo-terminal (PTY) running your real interactive shell, presenting a clean, modern interface directly inside your existing terminal emulator (Ghostty, Terminal.app, iTerm2, WezTerm, Alacritty, Kitty).

A Composer That Stays Put

Dock your editor at the Bottom, pin it at the Top, or let it follow the output in Flow mode. Supports true multiline editing (Shift+Enter), persistent history, and zero prompt jumping.

Asynchronous Semantic Highlighting

Commands, flags, builtins, and paths are tokenized and checked against your live shell environment in the background. Partial input is never blindly executed.

Usable, Searchable Transcripts

Command execution blocks capture exit status and elapsed runtime. Use /find to search output, /filter to isolate streams, and /copy to extract clean, uncolored plain text.

Persistent Daemon Sessions

Closing your terminal window detaches the frontend instead of terminating the shell process. Long-running jobs continue running; reattach effortlessly with nmsh --attach.

Architectural Principles

  +-------------------------------------------------------------+
  |              Terminal Host (Ghostty / Kitty / etc.)         |
  +-------------------------------------------------------------+
                                |  Raw PTY Input / VT Escapes
                                v
  +-------------------------------------------------------------+
  |                  NMSh Terminal App Frontend                 |
  |  - Docked Composer (Flow / Bottom / Top)                    |
  |  - Semantic Syntax Highlighter (Worker / Lexer)             |
  |  - Screen Plan Geometry Engine & Follow/Detached Viewport   |
  +-------------------------------------------------------------+
                                |  Targeted PTY Interaction
                                v
  +-------------------------------------------------------------+
  |             Persistent Shell Session (PTY Daemon)           |
  |             zsh  |  Bash 4.4+  |  Fish 3.1+                 |
  +-------------------------------------------------------------+

1. Persistent Real Shell State

NMSh never executes commands by isolated subshell spawning. Environment variables, aliases, shell functions, directory stacks, and history remain intact across commands because the same shell process runs continuously.

2. Zero Prompt Contention

External prompts like Starship, Oh My Posh, and Powerlevel10k run cleanly through NMSh Native context extraction or prompt adapters. Shell UI frameworks (e.g. ZLE, Oh My Zsh) never fight NMSh for terminal ownership.

3. Pure Text Integrity

Raw terminal output from PTY stdout and stderr remains presentation-safe. NMSh never recolors arbitrary output or mangles binary streams. Fullscreen terminal applications (Vim, Less, Htop, Tmux) drop directly into zero-overhead passthrough mode.

Free, open source, and built for developers who care about their terminal craft.