refactor: expose all scripts as modules

pkgs/cnf/default.nix

@@ -0,0 +1,40 @@
+{ writeShellApplication, ncurses, nix-index }:
+
+writeShellApplication {
+  name = "cnf";
+  runtimeInputs = [ ncurses nix-index ];
+  text = ''
+    command_not_found_handle () {
+        if [ -n "''${MC_SID-}" ] || ! [ -t 1 ]; then
+            >&2 echo "$1: command not found"
+            return 127
+        fi
+
+        echo -n "searching nix-index..."
+        ATTRS=$(nix-locate --minimal --no-group --type x --type s --top-level --whole-name --at-root "/bin/$1")
+
+        case $(echo -n "$ATTRS" | grep -c "^") in
+            0)
+                >&2 echo -ne "$(tput el1)\r"
+                >&2 echo "$1: command not found"
+                ;;
+            *)
+                >&2 echo -ne "$(tput el1)\r"
+                >&2 echo "The program ‘$(tput setaf 4)$1$(tput sgr0)’ is currently not installed."
+                >&2 echo "It is provided by the following derivation(s):"
+                while read -r ATTR; do
+                    ATTR=''${ATTR%.out} # Strip trailing '.out'
+                    >&2 echo "  $(tput setaf 12)nixpkgs#$(tput setaf 4)$ATTR$(tput sgr0)"
+                done <<< "$ATTRS"
+        esac
+
+        return 127
+    }
+
+    command_not_found_handler () {
+        command_not_found_handle "$@"
+        return $?
+    }
+
+  '';
+}