[clever@amd-nixos:~]$ find input-dir/
input-dir/
input-dir/foo
input-dir/bar
input-dir/baz.o
[clever@amd-nixos:~]$ nix-build filtersource.nix
these derivations will be built:
/nix/store/h3psl2ywl0n2grn5vnybpshgfy77i1wc-filterSource-example.drv
building path(s) ‘/nix/store/r1b2vj7889mx0x5bk8wd8km4y079hfmq-filterSource-example’
source contains:
/nix/store/1qixzdq7c1yixih637c86973dnyfs4h6-input-dir
/nix/store/1qixzdq7c1yixih637c86973dnyfs4h6-input-dir/bar
/nix/store/1qixzdq7c1yixih637c86973dnyfs4h6-input-dir/foo
done
/nix/store/r1b2vj7889mx0x5bk8wd8km4y079hfmq-filterSource-example
[clever@amd-nixos:~]$