# Practical Nixos

A non-exhaustive list of the things I do to make NixOS work for me. Because at the end of the day software purity is nice, but I still need to actually get work done.

## Get NixOS to check my recently populated cache

narinfo-cache-negative-ttl

## Get the originating flake info for a running system-path

nix-store -q --deriver /run/current-system | nix flake metadata

## Building only the ‘system-path’

Get the ‘system-path’ store path

nix derivation show `oizys output` | jq -r '.[].inputDrvs | with_entries(select(.key|match("system-path";"i"))) | keys | .[]'

Build the ‘system-path’

nix build '/path/to/system-path.drv^*' --log-lines 0 --print-build-logs

## Micromamba

Start a shell with a functional micromamba.

alias micromamba-fhs="nix-shell -E 'with import <nixpkgs> {}; (pkgs.buildFHSUserEnv {name = \"fhs\"; runScript=\"zsh\";}).env'"

## Existing Python Venv

## Vscode

Just use vscode-fhs and move on with your life.

## Distrobox

I made a custom distrobox as one of the ultimate fallbacks.

## Build Failures

If I am suddenly needing to build something that is usually built by nixos I need to check if build failures are happening on hydra. If they aren’t it means I’ve changed the closure somehow, otherwise the error is upstream and should in theory be resolved eventually.

The ui for hydra is kind of a nightmare. But there is hydra-check for the fastest check of single package.

## Ongoing problems

### Python

Error from matplotlib:

ImportError: libstdc++.so.6: cannot open shared object file: No such file or directory

There are a number of ways to solve this the most attractive being to use nix-ld. However, I run into an issues because qtile is corrupting the environment and taking precedence over the python wrapper that I add to /run/current-system/sw/bin.