https://blog.dtsykunov.com/tags/devtools/Recent content in Devtools on dtsykunov — blogHugoen-usSat, 04 Apr 2026 12:56:20 +0000https://blog.dtsykunov.com/posts/nix-dev-env-claude-code/Sat, 04 Apr 2026 00:00:00 +0000https://blog.dtsykunov.com/posts/nix-dev-env-claude-code/<p>Claude Code runs each Bash command in its own process. Environment variables don&rsquo;t persist between them — an <code>export</code> in one invocation is gone by the next.</p> <p>If your project uses a Nix devShell, this is a problem. Running <code>nix develop</code> inside a Claude session is messy, and running outside it requires restarting the devShell and Claude for any new dependency added to <code>flake.nix</code>.</p> <h2 id="claude_env_file"><code>CLAUDE_ENV_FILE</code></h2> <p>Claude Code has a <a href="https://code.claude.com/docs/en/env-vars"><code>CLAUDE_ENV_FILE</code></a> environment variable. Set it to a shell script path before launching, and Claude will source that script before every Bash command it runs.</p>