G-Shell

A POSIX-compliant shell written in Rust — built from scratch as part of the CodeCrafters "Build Your Own Shell" challenge.

Features

• Builtins: echo, pwd, cd, type, exit, history, export, unset, set, env, test/[, alias/unalias, source, help
• Pipes & redirects: |, >, >>, <, 2>, 2>>, 2>&1, heredocs (<<)
• Scripting: if/elif/else/fi, for/do/done, while/do/done, case/in/esac, subshells ( )
• Operators: &&, ||, ;, & (background), ! (pipeline negation)
• Expansion: $VAR, ${VAR}, $?, $(cmd), `cmd`, ~, globs (*?[a-z]), history expansion (!!, !$, !N)
• Tab completion: builtins + PATH lookup + filesystem
• Custom theme system:
  • GS_PROMPT_FORMAT — segment-based prompt ({user}, {host}, {path}, {git}, {exit}, etc.)
  • GS_OH_MY_POSH_THEME — load oh-my-posh .omp.json themes
  • GS_STYLE_<SEGMENT> — per-segment colors ("cyan bold", "white on_blue", hex "#ff0000")
  • Legacy PS1 backslash escapes still supported (\w, \u, \h, \$, \t)
• REPL: multi-line input, history save/load, HISTFILE, ! history expansion, Ctrl+C handling
• Init file: ~/.gshellrc or $GSHELLRC sourced on startup

Install

Prerequisites

• Rust 1.91+ (rustup install 1.91 && rustup default 1.91)

One-liner (curl | sh)

sh -c "$(curl -fsSL https://raw.githubusercontent.com/Crazygiscool/G-shell/main/install.sh)"

Downloads and runs install.sh — builds the release binary and installs to ~/.local/bin.

Arch Linux (AUR)

yay -S g-shell
# or: paru -S g-shell

Builds from source. Requires base-devel and cargo.

Via install.sh (manual)

git clone https://github.com/Crazygiscool/G-shell
cd G-shell
chmod +x install.sh
./install.sh               # installs to ~/.local/bin
./install.sh /usr/local/bin  # custom path

Via cargo

cargo install --path .

From source (no install)

./gshell.sh           # build debug + run
./gshell.sh --bin     # build release + run

Quick start

g-shell

Or customize the prompt in ~/.gshellrc:

export GS_PROMPT_FORMAT='{user}@{host}:{path}{git}{exit} {prompt} '
export GS_STYLE_PATH="cyan bold"
export GS_STYLE_GIT="yellow"

Oh-my-posh themes:

export GS_OH_MY_POSH_THEME="$HOME/.poshthemes/catppuccin.omp.json"

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CodeCrafters

This project originated from the CodeCrafters "Build Your Own Shell" challenge.

Passing the first stage

git commit -am "pass 1st stage" # any msg
git push origin master

Stage 2 & beyond

1. Ensure you have cargo (1.91) installed locally
2. Run ./your_program.sh to run your program
3. Commit your changes and run git push origin master to submit your solution