elaOnMars · April 26, 2018 22:54 · Apr 26, 2018
diff --git a/NixOS_Delete_store_builds.txt b/NixOS_Delete_store_builds.txt
@@ -0,0 +1,86 @@
+## View NixOS builds:
+ls -l /nix/var/nix/profiles/
+
+<snip>
+lrwxrwxrwx 1 root root   14 25. Apr 01:29 default -> default-1-link
+lrwxrwxrwx 1 root root   60 25. Apr 01:29 default-1-link -> /nix/store/1ny6g20kvqq5xq0vrby49k6alpa76xhn-user-environment
+drwxrwxrwt 6 root root 4096 25. Apr 18:21 per-user
+lrwxrwxrwx 1 root root   13 25. Apr 16:49 system -> system-9-link
+lrwxrwxrwx 1 root root   88 24. Apr 15:49 system-1-link -> /nix/store/jvl660mg3xhh5mq5hrnwjc3qmvr2i3j-nixos-system-me-18.03.131807.489a14add9a
+lrwxrwxrwx 1 root root   88 24. Apr 16:25 system-2-link -> /nix/store/61q3125mq5hrnwkaml9hr18vyz1i6kh1-nixos-system-me-18.03.131807.489a14add9a
+lrwxrwxrwx 1 root root   88 24. Apr 17:04 system-3-link -> /nix/store/prk88pz5mq5hrnwffmp5bkbrxywfawl-nixos-system-me-18.03.131807.489a14add9a
+</snip>
+or
+
+nix-env -p /nix/var/nix/profiles/system --list-generations
+<snip>
+0       default
+4,0K    default-1-link
+180K    per-user
+0       system
+4,0K    system-1-link
+4,0K    system-2-link
+4,0K    system-3-link
+</snip>
+
+
+To have an idea which programs are actually installed in
+each build run
+ls on the sw/bindirectory of the system links.
+
+
+
+Remove build #2 and the files with it:
+
+$ nix-store --delete /nix/store/prk88pz5mq5hrnwffmp5bkbrxywfawl-nixos-system-me-18.03.131807.489a14add9a/
+
+finding garbage collector roots...
+0 store paths deleted, 0.00 MiB freed
+error: cannot delete path '/nix/store/prk88pz5mq5hrnwffmp5bkbrxywfawl-nixos-system-me-18.03.131807.489a14add9a' since it is still alive
+
+# Check if this build is active:
+$ nix-store --query --roots /nix/store/prk88pz5mq5hrnwffmp5bkbrxywfawl-nixos-system-me-18.03.131807.489a14add9a/
+/nix/var/nix/profiles/system-2-link
+$
+
+An active build would look like:
+/nix/var/nix/profiles/system-5-link
+/run/booted-system
+$
+
+# Remove system-2-link also if it marked as active:
+$ nix-env -p /nix/var/nix/profiles/system --delete-generations 2
+
+# To remove system-5-link run
+$ nix-env -p /nix/var/nix/profiles/system --delete-generations 5
+
+
+# To free up space run again:
+$ nix-store --delete /nix/store/prk88pz5mq5hrnwffmp5bkbrxywfawl-nixos-system-me-18.03.131807.489a14add9a
+finding garbage collector roots...
+removing stale link from '/nix/var/nix/gcroots/auto/vzqgby05kf44a8dfi4fr0rf0y1zfyn9f' to '/tmp/nixos-rebuild.YLJWU0/nix.drv'
+removing stale link from '/nix/var/nix/gcroots/auto/fqbzfzxcgykd9xkv3kzfxrnv8h6q1d8i' to '/tmp/nixos-rebuild.YLJWU0/nix'
+deleting '/nix/store/prk88pz5mq5hrnwffmp5bkbrxywfawl-nixos-system-me-18.03.131807.489a14add9a'
+deleting '/nix/store/trash'
+deleting unused links...
+note: currently hard linking saves 1858.32 MiB
+1 store paths deleted, 0.04 MiB freed
+
+# Deleting the 2nd generation made more garbage. You need to remove it with:
+$ nix-collect-garbage
+finding garbage collector roots...
+deleting garbage...
+deleting '/nix/store/nmmb8rf1rkazgcs2myfabp74xr80f8wr-linux-4.14.34-rt27.lock'
+deleting '/nix/store/nw6f7max04q2lwxc7lslv4mm5r8hq6r8-linux-4.14.34-rt27-dev.lock'
+deleting '/nix/store/i8jhy3mz6bnzh9la5vv9cp4cpw0dqgkf-nixos-system-gudrun-18.03.132083.06c576b0525.drv'
+deleting '/nix/store/xbmz2gbbn83zr7039xxrp3wx2kdk22hi-etc.drv'
+deleting '/nix/store/4flyh7mjrdybw8w1zi912flin3p0kjpy-system-units.drv'
+...
+deleting unused links...
+note: currently hard linking saves 1777.59 MiB
+146 store paths deleted, 435.51 MiB freed
+
+
+
+Alternatively you can run 
+$ nix-collect-garbage --max-freed 1g