Install Dev Tools

Install / update dev tools (uv, Go, nvm)

Goal

Keep three developer tools current, installed per-user (no sudo), each fetched from its official source — and placed so that their unbounded caches don't threaten the root filesystem.

This skill manages nvm itself, not Node — run nvm install --lts afterward.

Why layout matters (read this first)

On these machines $HOME is a bind mount of a subdirectory on the same partition as /. df ~ and df / print two lines that look independent while reporting one device, so it's easy to miss. The consequence: anything unbounded landing in $HOME fills /, and a full root filesystem wedges the machine — systemd, journald and /tmp all lose the ability to write. This has actually happened to the user.

Go's module cache and nvm's Node versions are exactly that kind of growth:

So scripts/lib.sh resolves an install prefix: $DEV_TOOLS_PREFIX if set, else the first writable candidate (/local-ssd/$USER, /scratch/$USER, /local/$USER) that is on a different filesystem than /, else $HOME/.local. Being a separate filesystem is the whole criterion — a roomier directory on the root partition wouldn't protect /. That gives two modes:

Every path is overridable from the environment, and an already-exported value wins — so a machine configured by a previous run is detected as configured, not reinstalled somewhere new.

The core rule

Audit first, then ask before changing anything. The audit is read-only. Each tool is installed or moved only after the user confirms that specific tool.

Workflow

1. Audit (read-only, always safe)

bash scripts/audit.sh

Reports the filesystem situation (whether $HOME shares /, free space, the resolved prefix and every install target), then installed vs. latest official version per tool with a verdict: missing, update-available, up-to-date, or unknown (couldn't resolve latest — offline or a proxy blocking the GitHub API).

--tsv gives machine-readable rows (name<TAB>installed<TAB>latest<TAB>verdict).

Run this in a login shell (bash -lic 'bash scripts/audit.sh'). A non-login shell may carry a stale environment snapshot that lacks the user's PATH and NVM_DIR, making installed tools look missing.

2. Report

Show the table. Lead with the filesystem finding if $HOME shares / — that's usually news to the user and it's what justifies the layout. Then call out which tools are missing or update-available, with current → target versions.

3. Ask per tool

For each tool needing work, ask before touching it. Do not batch-upgrade. Skip anything up-to-date. If unknown, say the latest couldn't be resolved and skip unless the user gives an explicit --version.

4. Install (only what the user approved)

bash scripts/install-tool.sh <uv|go|nvm>            # latest official
bash scripts/install-tool.sh go --version 1.23.4    # a specific version
bash scripts/install-tool.sh uv --dry-run           # preview, no changes

The script prints a plan line, prompts for itself, and honors --yes when the user already confirmed in conversation.

5. Wire up caches and the shell rc

bash scripts/setup-env.sh                # show the plan, change nothing
bash scripts/setup-env.sh --apply        # do it, prompting per change

This makes ~/.cache a symlink to the prefix, appends a marker-delimited block to the shell rc (~/.bashrc.mine if present, else ~/.bashrc), and checks for rc lines that would override it. Backs up the rc first; idempotent — re-running replaces its own block rather than duplicating it.

6. Verify in a new login shell

bash -lic 'go env GOROOT GOPATH GOMODCACHE GOCACHE; command -v uv; echo $NVM_DIR; nvm ls'

Then prove it end-to-end: build a trivial Go program and confirm the cache landed on the prefix and nothing appeared in $HOME.

Notes & gotchas

• Never export GOROOT. The go binary derives it from its own real path, resolving symlinks correctly — verified through a /usr/local/bin symlink. A hardcoded GOROOT silently breaks builds the moment the toolchain moves, which is exactly how a previous setup went stale.
• Getting go onto PATH. Either add $GO_INSTALL_DIR/bin, or sudo ln -s $GO_INSTALL_DIR/bin/{go,gofmt} /usr/local/bin/. Symlink gofmt too — editors and go vet shell out to it.
• Move nvm, don't reinstall it. install-tool.sh nvm detects an existing ~/.nvm that belongs on the prefix and offers to mv it. A fresh install.sh into a new NVM_DIR yields an empty nvm: installed Node versions and the default -> lts/* alias live in the old directory and get abandoned. Moving is safe — Node binaries are path-independent and global packages use #!/usr/bin/env node shebangs. Check first that nothing is running on that Node.
• Installer-appended rc lines can silently win. The uv and nvm installers append their setup to the end of ~/.bashrc. When the managed block lives in a file that ~/.bashrc sources (the usual ~/.bashrc.mine arrangement), those appended lines run afterwards and override it. nvm's hardcodes NVM_DIR="$HOME/.nvm". The symptom is nasty: node and npm keep working because PATH was already set, while NVM_DIR points at a directory that may not exist — nothing looks wrong until the next nvm install. setup-env.sh checks for this; re-check after any reinstall.
• Symlink ~/.cache, don't just set XDG_CACHE_HOME. Plenty of tools hardcode ~/.cache and ignore the variable, and the symlink covers tools installed in future with no further configuration.
• Cache contents are never copied. They're regenerable by definition, so setup-env.sh moves an existing ~/.cache aside to ~/.cache.old and leaves it for the user to delete.
• Don't run rm -rf. It's blocked in this user's permission setup. Move things aside and hand them a !-prefixed command to delete.
• Gate rc blocks on the volume existing, never on hostname. A hostname test protects the one machine it was written for and fails silently on every other — which is how an earlier [ "$(hostname)" = '<some-host>' ] block ended up doing nothing on a second machine for months, leaving GOROOT/GOPATH unset there while looking correct in the file.
• Official sources only. No third-party mirrors, no distro package managers.
• No sudo for installs; only the optional /usr/local/bin symlinks need it.
• Go upgrades replace the install dir wholesale per Go's official guidance — it does not merge over an old tree. Only $GO_INSTALL_DIR is touched.
• Offline / proxied. If latest can't be resolved the audit shows unknown (the GitHub API is often blocked while go.dev and astral.sh still work); pass --version to install a known version explicitly.
• Environment overrides: DEV_TOOLS_PREFIX, GO_INSTALL_DIR, UV_INSTALL_DIR, NVM_DIR, DEV_CACHE_DIR, DEV_GOPATH.