NW | 2026-mar-sdc | Zabihollah Namazi | Sprint 3 | implement shell tools

implement-shell-tools/cat/cat.js

@@ -0,0 +1,48 @@
+import { promises as fs } from "node:fs";
+
+// get all command line arguments after "node cat.js" - like -n or -b
+const args = process.argv.slice(2);
+
+// put them in variables
+const showAllNumbers = args.includes("-n");
+const showNonEmptyNumbers = args.includes("-b");
+
+// getting the paths of files
+const paths = args.filter(arg => arg !== "-n" && arg !== "-b");
+
+// helper: mimic real cat line number formatting
+const padLineNumber = (num) => String(num).padStart(6, " ");
+
+// loop over each file
+for (const path of paths) {
+  try {
+    // read file as text
+    const content = await fs.readFile(path, "utf-8");
+
+    // split them into lines
+    const lines = content.split("\n");
+
+    let lineNumber = 1; // tracks line numbers for -b and -n
+
+    for (const line of lines) {
+      if (showNonEmptyNumbers) {
+        // -b: number only non-empty lines
+        if (line !== "") {
+          console.log(`${padLineNumber(lineNumber)}  ${line}`);
+          lineNumber++;
+        } else {
+          console.log(line); // shows empty line with no number
+        }
+      } else if (showAllNumbers) {
+        // -n: number all lines
+        console.log(`${padLineNumber(lineNumber)}  ${line}`);
+        lineNumber++;
+      } else {
+        // no flags: just print line
+        console.log(line);
+      }
+    }
+  } catch (err) {
+    console.error(`Error reading file "${path}": ${err.message}`);
+  }
+}

implement-shell-tools/ls/ls.js

@@ -0,0 +1,41 @@
+import { promises as fs } from "node:fs";
+
+//getting all commands 
+const args = process.argv.slice(2);
+
+const showOnePerLine = args.includes("-1"); 
+const showAllFilesWithHidden = args.includes("-a");
+
+//current path
+const path = args.find(arg => !arg.startsWith("-")) || ".";
+// if we do console.log("path=> ",path," args=> " ,args); it will give us this =>: path=>  sample-files  args=>  [ '-1', '-a', 'sample-files' ]
+
+try {
+  const direc = await fs.readdir(path);
+
+  // handle hidden files (-a flag controls this)
+  let files = direc;
+
+  if (!showAllFilesWithHidden) {
+    files = files.filter(file => !file.startsWith("."));
+  }
+
+  // one file per line
+  if (showOnePerLine) {
+    files.forEach(file => {
+      console.log(file);
+    });
+  }
+
+  // default behavior: also one per line (simple version of ls)
+  else {
+    files.forEach(file => {
+      console.log(file);
+    });
+  }
+
+} catch (err) {
+  console.error(`Error reading directory "${path}": ${err.message}`);
+}
+
+

implement-shell-tools/wc/README.md

@@ -14,4 +14,4 @@ It must act the same as `wc` would, if run from the directory containing this RE
 
 Matching any additional behaviours or flags are optional stretch goals.
 
-We recommend you start off supporting no flags for one file, then add support for multiple files, then add support for the flags.
+We recommend you start off supporting no flags for one file, then add support for multiple files, then add support for the flags

implement-shell-tools/wc/wc.js

@@ -0,0 +1,55 @@
+import { promises as fs } from "node:fs";
+
+const args = process.argv.slice(2);
+
+const showLines = args.includes("-l");
+const showWords = args.includes("-w");
+const showChars = args.includes("-c");
+let paths = args.filter(arg => !arg.startsWith("-"));
+if (paths.length === 0) paths = ["."];
+
+// helper for formatting like real wc
+const pad = (n) => String(n).padStart(8, " ");
+
+let totalLines = 0;
+let totalWords = 0;
+let totalChars = 0;
+
+for (const path of paths) {
+    try {
+        const content = await fs.readFile(path, "utf-8");
+
+        const lines = content.split("\n").length;
+        const words = content.split(/\s+/).filter(Boolean).length;
+        const chars = content.length;
+
+        totalLines += lines;
+        totalWords += words;
+        totalChars += chars;
+
+    } catch (err) {
+        console.error(`Error reading file "${path}": ${err.message}`);
+    }
+
+}
+if (showLines) {
+    console.log("lines:", totalLines);
+}
+
+if (showWords) {
+    console.log("words:", totalWords);
+}
+
+if (showChars) {
+    console.log("chars:", totalChars);
+}
+
+
+// default output when no flags
+if (!showLines && !showWords && !showChars) {
+    console.log(
+    `${pad(totalLines)}\t${pad(totalWords)}\t${pad(totalChars)}\ttotal`
+  );
+}
+
+