fgm

fgm is a Go version manager written in Rust (macOS/Linux first). It supports downloading/installing, switching, listing, uninstalling, printing the current version, and cleaning cache.

Features

• Install: install <version> (supports go1.22.4 / 1.22.4 / 1.22 / latest)
• Switch: use <version>
• Current: current
• List installed: list
• Uninstall: uninstall <version>
• Latest stable: latest
• Cache: cache dir|size|clean
• Diagnose: doctor

Install

curl -fsSL https://raw.githubusercontent.com/coderbaozi/fgm/main/scripts/install.sh | sh

Optional environment variables:

• FGM_BIN_DIR: default ~/.local/bin

Quick start

1. Install and switch to a version:

fgm install 1.22 --use
fgm current

2. Ensure PATH includes the shim directory (default: ~/.fgm/bin):

export PATH="$HOME/.fgm/bin:$PATH"

3. Switch versions:

fgm use 1.22.4
go version

Version resolution rules

• latest: fetch the latest stable tag via https://go.dev/VERSION?m=text (or an equivalent URL based on --mirror).
• 1.22.4 / go1.22.4: install the specified patch directly.
• 1.22: resolve to the latest stable patch under the same minor (e.g. go1.22.4).
  • Resolution: request {mirror}/?mode=json&include=all, filter stable=true entries under the same minor, and pick the highest patch.

Directory layout (default)

Root: ~/.fgm

• ~/.fgm/versions/<tag>/go: extracted Go installation directory
• ~/.fgm/cache: download cache (.tar.gz)
• ~/.fgm/current: symlink pointing to the current version
• ~/.fgm/bin/go, ~/.fgm/bin/gofmt: shims (symlinks to current/go/bin/*)

Global options

• --root <DIR>: set fgm root directory (default: ~/.fgm)
• --mirror <URL>: set download mirror (default: https://go.dev/dl)
• --quiet: reduce output
• --verbose: print more debug information

Example:

fgm --mirror https://go.dev/dl install 1.22 --use

Verification & overwrite

• SHA256 verification is enabled by default; use install --no-verify to skip.
• If the target version already exists, use install --force to overwrite.

Troubleshooting

fgm doctor
fgm cache size
fgm cache clean

Known limitations

• Windows is not supported for now (the shim relies on symlink).
• If the mirror specified by --mirror does not support /dl/?mode=json, install 1.22 cannot resolve the latest patch automatically (use the default https://go.dev/dl or a compatible mirror).