Here are some notes about my NixOS system

nixos-version --json | jq -r .nixpkgsRevision

From: https://www.tweag.io/blog/2020-07-31-nixos-flakes/

sudo nixos-rebuild switch --flake '/etc/nixos#pedroregispoar'

sudo \
su \
-c \
"nix flake update && nixos-rebuild switch --flake '/etc/nixos#pedroregispoar'"

sudo \
su \
-c \
'
  nix \
    store \
    gc \
    --verbose \
    --option keep-derivations false \
    --option keep-outputs false \
  && nix-collect-garbage --delete-old \
  && nix store optimise --verbose
'

To list all generations:

sudo nix-env --profile /nix/var/nix/profiles/system --list-generations

nix profile list --profile "${HOME}"/.nix-profile

nix show-derivation --recursive /run/current-system

Lists entries from /boot/loader/entries:

ls -al /boot/loader/entries

sudo nix-env --profile /nix/var/nix/profiles/system --delete-generations old

sudo nix --extra-experimental-features nix-command profile history --profile /nix/var/nix/profiles/system

Be carefull, this may break the system!

nix --extra-experimental-features nix-command profile wipe-history --profile /nix/var/nix/profiles/system

sudo bash -c "cd /boot/loader/entries; ls | xargs echo"

sudo bash -c "cd /boot/loader/entries; ls | grep -v 'nixos-generation-13.conf' | xargs rm"

Adapted from:

readlink "$(readlink ~/.nix-profile)"

nix-env --list-generations | grep current | awk '{print $1}'

tree /nix/var/nix/profiles

sudo nix-env --list-generations --profile /nix/var/nix/profiles/system

sudo nix-env --list-generations --profile /nix/var/nix/profiles/system | grep current | awk '{print $1}'

Current generation number

how to find which packages are installed system-wide in NixOS?. I think it is related, what about packages intalled with nix-shell? See nix-env --query --installed --out-path | cat and https://nixos.wiki/wiki/Nix_command/profile and https://www.reddit.com/r/NixOS/comments/j4k2zz/does_anyone_use_flakes_to_manage_their_entire/ghrs271/?utm_source=reddit&utm_medium=web2x&context=3

TODO:

Building this NixOS system using only nix (in future it is going to be the nix static one):

nix \
build \
github:PedroRegisPOAR/NixOS-configuration.nix#nixosConfigurations.pedroregispoar.config.system.build.toplevel

ls -al result/init

ls -al /nix/store | rg podman

nix-store --query --roots /nix/store/lr4k6wly0akiqmwqx573vja08c0gx91y-unit-podman.service

git remote set-url origin $(git remote show origin | grep "Fetch URL" | sed 's/ *Fetch URL: //' | sed 's/https:\/\/github.com\//git@github.com:/')

From: TODO

git rm --cached <file>

# or

git rm -r --cached <folder>

From: https://stackoverflow.com/a/1274447

git config --list

git config user.name \
&& git config user.email

cat << EOF > ~/.gitconfig
[user]
    name = Pedro O. A. Regis
    email = pedroalencarregis@hotmail.com
EOF

For flake systems:

nix repl> :lf /etc/nixos
nix repl> nixosConfigurations.<hostname>

From: https://www.reddit.com/r/NixOS/comments/u6fl8j/how_to_the_entire_configurationnix_into_nix_repl/

PedroRegisPOAR / NixOS-configuration.nix

readme

Here are some notes about my NixOS system