add shell environment

.envrc

@@ -0,0 +1 @@
+use nix

shell.nix

@@ -0,0 +1,30 @@
+let
+  pkgs = import <nixpkgs> {
+    overlays = [
+      (final: prev: {
+        python3 = prev.python3.override {
+          packageOverrides = pythonFinal: pythonPrev: {
+            python-escpos = pythonPrev.python-escpos.overrideAttrs (oldAttrs: {
+              version = "0.0.0+unstable-2024-10-10";
+              src = oldAttrs.src.override {
+                rev = "7d42f117161362e99c56431ebeb2ef1e9c91c495";
+                hash = "sha256-Wl7naHbsYfN+VYASQXyWrLNF953nwoM0ugiutE2jYNI=";
+              };
+            });
+          };
+        };
+      })
+    ];
+  };
+  devshell = import <devshell> { };
+in
+
+# alias print="lp -d EPSON-TM-m30 -o lpi=10 -o cpi=15"
+devshell.mkShell {
+  packages = with pkgs; [
+    (python3.withPackages (p: with p; [
+      python-escpos
+      pycups
+    ]))
+  ];
+}