add overklay

default.nix

@@ -1,6 +1,15 @@
 let
-  # Import sources
-  sources = import ./nix/sources.nix;
+  sources = imports ./nix/sources.nix;
 
-# And return that specific nixpkgs
-in sources.nixpkgs
+  hello = pkgs.writeShellScriptBin "hello" ''
+    echo "Hello from the Nix channel overlay!"
+  '';
+
+  pkgs = import sources.nixpkgs {
+    overlays = [
+      (self: super: {
+        inherit hello;
+      })
+    ];
+  };
+in pkgs

nix/sources.json

@@ -5,22 +5,10 @@
         "homepage": null,
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "6c43a3495a11e261e5f41e5d7eda2d71dae1b2fe",
-        "sha256": "16f329z831bq7l3wn1dfvbkh95l2gcggdwn6rk3cisdmv2aa3189",
+        "rev": "2795c506fe8fb7b03c36ccb51f75b6df0ab2553f",
+        "sha256": "0m6prywp2axikm2sld8x6g362lzy2y8nf51w106j2riaklg6mfav",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/6c43a3495a11e261e5f41e5d7eda2d71dae1b2fe.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "xbuild": {
-        "branch": "master",
-        "description": "xbuild for all in one appimage integrated with tools for build environment",
-        "homepage": null,
-        "owner": "shen390s",
-        "repo": "xbuild",
-        "rev": "ca08d8d69df0881b944526d295c64bcf23951dd3",
-        "sha256": "1m5f6qa6z2r5yj83vwcciwm135gz9dngp2acad4j563qf9vii0l1",
-        "type": "tarball",
-        "url": "https://github.com/shen390s/xbuild/archive/ca08d8d69df0881b944526d295c64bcf23951dd3.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/2795c506fe8fb7b03c36ccb51f75b6df0ab2553f.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }