Comma runs software without installing it.
Basically it just wraps together nix shell -c and nix-index. You stick a , in front of a command to
run it from whatever location it happens to occupy in nixpkgs without really thinking about it.
comma is in nixpkgs so you can install it just like any other package.
either install it in your nix environment
nix-env -f '<nixpkgs>' -iA commaor add this snippet to your NixOS configuration.
environment.systemPackages = with pkgs; [ comma ];, cowsay neatoComma supports caching both the choices (i.e., once you select a derivation for
a command, it will always return the same derivation) and paths (i.e., once the
path is evaluated by Nix, we will always return the same path until it is GC'd).
You can control those options by using --cache-level flag or COMMA_CACHING
environment variable:
0: completely disables caching1: only cache choices2(default): also caches paths
Cache for path is the default since it makes subsequent usage of a command much faster:
$ hyperfine "./result/bin/comma --cache-level=1 ls" "./result/bin/comma --cache-level=2 ls"
Benchmark 1: ./result/bin/comma --cache-level=1 ls
Time (mean ± σ): 1.050 s ± 0.021 s [User: 0.540 s, System: 0.210 s]
Range (min … max): 1.009 s … 1.075 s 10 runs
Benchmark 2: ./result/bin/comma --cache-level=2 ls
Time (mean ± σ): 6.6 ms ± 1.0 ms [User: 3.0 ms, System: 3.5 ms]
Range (min … max): 5.8 ms … 11.3 ms 297 runs
Warning: Statistical outliers were detected. Consider re-running this benchmark on a quiet system without any interferences from other programs. It might help to use the '--warmup' or '--prepare' options.
Summary
./result/bin/comma --cache-level=2 ls ran
159.25 ± 23.44 times faster than ./result/bin/comma --cache-level=1 ls
However, it also means you may not run the most up-to-date version of a
command, specially if you don't run Nix's garbage collector often. If this is
an issue for you, set COMMA_CACHING=1.