add cat

react/resume/src/emulator/commands/cat.js

@@ -1,5 +1,29 @@
-const fs = require('fs');
+import { Terminal } from 'xterm';
+const fs = require('../fs');
 
+/**
+ * 
+ * @param { string[] } argv 
+ * @param { Terminal } terminal 
+ */
 module.exports = (argv, terminal) => {
-    terminal.writeln('hi')
+    if (argv.indexOf('--help') != -1) {
+        terminal.writeln('Usage: cat [file] [-n]');
+        terminal.writeln('  -n --number: show lines numbers');
+        terminal.writeln('     --help:   show this help');
+        return;
+    }
+    const numbers = (argv.indexOf('-n') != -1) || (argv.indexOf('--number') != -1);
+    
+    let files = argv.filter(x => { return !x.startsWith('-') });
+    files.shift();
+    files.forEach(file => {
+        const lines = fs.readFileSync(file).toString().split('\n');
+        let i = 1;
+        lines.forEach(line => {
+            if (numbers) terminal.write('\033[35m' + i + ' |\033[0m ');
+            terminal.writeln(line);
+            i++;
+        })
+    })
 }