Create cat.mjs file and define the initial implementation

Author: anosidium

implement-shell-tools/cat/cat.mjs

@@ -0,0 +1,12 @@
+import { program } from "commander";
+import { promises as fs } from "node:fs";
+
+program.name("cat");
+program.description("simple cat clone");
+program.option("-n, --number", "number all output lines");
+program.option("-b, --number-nonblank", "number non-empty output lines");
+program.argument("[paths...]", "file(s) to process");
+program.parse();
+
+const { number, numberNonblank } = program.opts();
+const paths = program.args;