From 7045902ca90cfd1128f44f7ccb6cef927c787b4d Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Thu, 12 Mar 2026 23:57:54 +0000
Subject: [PATCH 01/11] feat(cat): add initial implementation of cat command to
 read and output file contents

---
 implement-shell-tools/cat/cat.js            | 17 +++++++++++++++++
 implement-shell-tools/cat/package-lock.json | 21 +++++++++++++++++++++
 implement-shell-tools/cat/package.json      |  6 ++++++
 3 files changed, 44 insertions(+)
 create mode 100644 implement-shell-tools/cat/cat.js
 create mode 100644 implement-shell-tools/cat/package-lock.json
 create mode 100644 implement-shell-tools/cat/package.json

diff --git a/implement-shell-tools/cat/cat.js b/implement-shell-tools/cat/cat.js
new file mode 100644
index 000000000..5c67a908e
--- /dev/null
+++ b/implement-shell-tools/cat/cat.js
@@ -0,0 +1,17 @@
+import { program } from "commander";
+import * as fs from "node:fs/promises";
+
+program
+  .name("cat")
+  .description("Reads file and writes it to the standard output")
+  .argument("<path>", "The file path to process");
+
+program.parse();
+
+try {
+  const [filePath] = program.args;
+  const contents = await fs.readFile(filePath, { encoding: "utf8" });
+  console.log(contents);
+} catch (err) {
+  console.error(err.message);
+}
diff --git a/implement-shell-tools/cat/package-lock.json b/implement-shell-tools/cat/package-lock.json
new file mode 100644
index 000000000..6179cab28
--- /dev/null
+++ b/implement-shell-tools/cat/package-lock.json
@@ -0,0 +1,21 @@
+{
+  "name": "cat",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "dependencies": {
+        "commander": "^14.0.3"
+      }
+    },
+    "node_modules/commander": {
+      "version": "14.0.3",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-14.0.3.tgz",
+      "integrity": "sha512-H+y0Jo/T1RZ9qPP4Eh1pkcQcLRglraJaSLoyOtHxu6AapkjWVCy2Sit1QQ4x3Dng8qDlSsZEet7g5Pq06MvTgw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=20"
+      }
+    }
+  }
+}
diff --git a/implement-shell-tools/cat/package.json b/implement-shell-tools/cat/package.json
new file mode 100644
index 000000000..043047a15
--- /dev/null
+++ b/implement-shell-tools/cat/package.json
@@ -0,0 +1,6 @@
+{
+  "type": "module",
+  "dependencies": {
+    "commander": "^14.0.3"
+  }
+}

From d373c0a57f2fb5d30c8cf50dab368d0b7c8e683b Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 00:28:09 +0000
Subject: [PATCH 02/11] feat(cat): enhance cat command with optional flags

---
 implement-shell-tools/cat/cat.js | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/implement-shell-tools/cat/cat.js b/implement-shell-tools/cat/cat.js
index 5c67a908e..6ecc56b34 100644
--- a/implement-shell-tools/cat/cat.js
+++ b/implement-shell-tools/cat/cat.js
@@ -4,14 +4,27 @@ import * as fs from "node:fs/promises";
 program
   .name("cat")
   .description("Reads file and writes it to the standard output")
-  .argument("<path>", "The file path to process");
+  .argument("<path>", "The file path to process")
+  .option("-n", "Number the output lines, starting at 1.")
+  .option("-b", "Number only non-blank output lines, starting at 1.");
 
 program.parse();
 
 try {
   const [filePath] = program.args;
-  const contents = await fs.readFile(filePath, { encoding: "utf8" });
-  console.log(contents);
+  const options = program.opts();
+
+  const file = await fs.open(filePath);
+
+  let lineNum = 1;
+  for await (const line of file.readLines()) {
+    const isBlank = line.trim() === "";
+    const shouldNumber = options.n || (options.b && !isBlank);
+
+    console.log(shouldNumber ? `${lineNum}  ${line}` : line);
+
+    if (shouldNumber) lineNum++;
+  }
 } catch (err) {
   console.error(err.message);
 }

From 975035e4eb9a0b9f7a81330aaabffa148a8be8a5 Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 01:02:07 +0000
Subject: [PATCH 03/11] feat(cat): update cat command to handle multiple file
 paths

---
 implement-shell-tools/cat/cat.js | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/implement-shell-tools/cat/cat.js b/implement-shell-tools/cat/cat.js
index 6ecc56b34..04ab1dcc9 100644
--- a/implement-shell-tools/cat/cat.js
+++ b/implement-shell-tools/cat/cat.js
@@ -3,27 +3,35 @@ import * as fs from "node:fs/promises";
 
 program
   .name("cat")
-  .description("Reads file and writes it to the standard output")
-  .argument("<path>", "The file path to process")
+  .description("Reads file(s) and writes them to the standard output")
+  .argument("<paths...>", "The file path(s) to process")
   .option("-n", "Number the output lines, starting at 1.")
   .option("-b", "Number only non-blank output lines, starting at 1.");
 
 program.parse();
 
 try {
-  const [filePath] = program.args;
+  const filePaths = program.args;
+
   const options = program.opts();
 
-  const file = await fs.open(filePath);
+  for (const filePath of filePaths) {
+    const file = await fs.open(filePath);
+
+    let lineNum = 1;
 
-  let lineNum = 1;
-  for await (const line of file.readLines()) {
-    const isBlank = line.trim() === "";
-    const shouldNumber = options.n || (options.b && !isBlank);
+    try {
+      for await (const line of file.readLines()) {
+        const isBlank = line.trim() === "";
+        const shouldNumber = options.n || (options.b && !isBlank);
 
-    console.log(shouldNumber ? `${lineNum}  ${line}` : line);
+        console.log(shouldNumber ? `${lineNum}  ${line}` : line);
 
-    if (shouldNumber) lineNum++;
+        if (shouldNumber) lineNum++;
+      }
+    } finally {
+      await file.close();
+    }
   }
 } catch (err) {
   console.error(err.message);

From d4a4f43923616f80d4a369ebe48c9dd2a134d3fb Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 05:52:35 +0000
Subject: [PATCH 04/11] feat(ls): add initial ls command to list current
 working directory contents

---
 implement-shell-tools/ls/ls.js             | 27 ++++++++++++++++++++++
 implement-shell-tools/ls/package-lock.json | 21 +++++++++++++++++
 implement-shell-tools/ls/package.json      |  6 +++++
 3 files changed, 54 insertions(+)
 create mode 100644 implement-shell-tools/ls/ls.js
 create mode 100644 implement-shell-tools/ls/package-lock.json
 create mode 100644 implement-shell-tools/ls/package.json

diff --git a/implement-shell-tools/ls/ls.js b/implement-shell-tools/ls/ls.js
new file mode 100644
index 000000000..7c1be50c5
--- /dev/null
+++ b/implement-shell-tools/ls/ls.js
@@ -0,0 +1,27 @@
+import { program } from "commander";
+import * as fs from "node:fs/promises";
+
+program
+  .name("ls")
+  .description("List directory contents")
+  .option("-a", "Include directory entries whose names begin with a dot ('.').")
+  .option("-1", "Force output to be one entry per line.");
+
+program.parse();
+
+try {
+  const options = program.opts();
+
+  const currentDir = process.cwd();
+  const files = await fs.readdir(currentDir);
+
+  if (options["1"]) {
+    for (const file of files) {
+      console.log(file);
+    }
+  } else {
+    console.log(...files);
+  }
+} catch (err) {
+  console.error(err.message);
+}
diff --git a/implement-shell-tools/ls/package-lock.json b/implement-shell-tools/ls/package-lock.json
new file mode 100644
index 000000000..082762764
--- /dev/null
+++ b/implement-shell-tools/ls/package-lock.json
@@ -0,0 +1,21 @@
+{
+  "name": "ls",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "dependencies": {
+        "commander": "^14.0.3"
+      }
+    },
+    "node_modules/commander": {
+      "version": "14.0.3",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-14.0.3.tgz",
+      "integrity": "sha512-H+y0Jo/T1RZ9qPP4Eh1pkcQcLRglraJaSLoyOtHxu6AapkjWVCy2Sit1QQ4x3Dng8qDlSsZEet7g5Pq06MvTgw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=20"
+      }
+    }
+  }
+}
diff --git a/implement-shell-tools/ls/package.json b/implement-shell-tools/ls/package.json
new file mode 100644
index 000000000..043047a15
--- /dev/null
+++ b/implement-shell-tools/ls/package.json
@@ -0,0 +1,6 @@
+{
+  "type": "module",
+  "dependencies": {
+    "commander": "^14.0.3"
+  }
+}

From 9f1261f26dbf23b97753849c2290e6339f633fa6 Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 06:16:36 +0000
Subject: [PATCH 05/11] feat(ls): add argument support for specifying directory
 path

---
 implement-shell-tools/ls/ls.js | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/implement-shell-tools/ls/ls.js b/implement-shell-tools/ls/ls.js
index 7c1be50c5..847a74c14 100644
--- a/implement-shell-tools/ls/ls.js
+++ b/implement-shell-tools/ls/ls.js
@@ -4,6 +4,10 @@ import * as fs from "node:fs/promises";
 program
   .name("ls")
   .description("List directory contents")
+  .argument(
+    "[path]",
+    "The file path to process (defaults to current directory)",
+  )
   .option("-a", "Include directory entries whose names begin with a dot ('.').")
   .option("-1", "Force output to be one entry per line.");
 
@@ -11,6 +15,10 @@ program.parse();
 
 try {
   const options = program.opts();
+  const [filePathArg] = program.args;
+
+  const filePath = filePathArg || process.cwd();
+  let files = await fs.readdir(filePath);
 
   const currentDir = process.cwd();
   const files = await fs.readdir(currentDir);

From 4abcb92186d0f1eb2f9760d571043bbb389c7549 Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 06:17:38 +0000
Subject: [PATCH 06/11] feat(ls): add logic to filter hidden files

---
 implement-shell-tools/ls/ls.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/implement-shell-tools/ls/ls.js b/implement-shell-tools/ls/ls.js
index 847a74c14..3a45b8c1c 100644
--- a/implement-shell-tools/ls/ls.js
+++ b/implement-shell-tools/ls/ls.js
@@ -20,8 +20,7 @@ try {
   const filePath = filePathArg || process.cwd();
   let files = await fs.readdir(filePath);
 
-  const currentDir = process.cwd();
-  const files = await fs.readdir(currentDir);
+  if (!options.a) files = files.filter((file) => !file.startsWith("."));
 
   if (options["1"]) {
     for (const file of files) {

From c6a7649af312483ba110fd8fa5a4a2e4049e0e3d Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 07:11:53 +0000
Subject: [PATCH 07/11] feat(wc): implement wc command for word, line, and byte
 counting

---
 implement-shell-tools/wc/package-lock.json | 21 ++++++++++++
 implement-shell-tools/wc/package.json      |  6 ++++
 implement-shell-tools/wc/wc.js             | 39 ++++++++++++++++++++++
 3 files changed, 66 insertions(+)
 create mode 100644 implement-shell-tools/wc/package-lock.json
 create mode 100644 implement-shell-tools/wc/package.json
 create mode 100644 implement-shell-tools/wc/wc.js

diff --git a/implement-shell-tools/wc/package-lock.json b/implement-shell-tools/wc/package-lock.json
new file mode 100644
index 000000000..c598ee9ca
--- /dev/null
+++ b/implement-shell-tools/wc/package-lock.json
@@ -0,0 +1,21 @@
+{
+  "name": "wc",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "dependencies": {
+        "commander": "^14.0.3"
+      }
+    },
+    "node_modules/commander": {
+      "version": "14.0.3",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-14.0.3.tgz",
+      "integrity": "sha512-H+y0Jo/T1RZ9qPP4Eh1pkcQcLRglraJaSLoyOtHxu6AapkjWVCy2Sit1QQ4x3Dng8qDlSsZEet7g5Pq06MvTgw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=20"
+      }
+    }
+  }
+}
diff --git a/implement-shell-tools/wc/package.json b/implement-shell-tools/wc/package.json
new file mode 100644
index 000000000..043047a15
--- /dev/null
+++ b/implement-shell-tools/wc/package.json
@@ -0,0 +1,6 @@
+{
+  "type": "module",
+  "dependencies": {
+    "commander": "^14.0.3"
+  }
+}
diff --git a/implement-shell-tools/wc/wc.js b/implement-shell-tools/wc/wc.js
new file mode 100644
index 000000000..30dd2607e
--- /dev/null
+++ b/implement-shell-tools/wc/wc.js
@@ -0,0 +1,39 @@
+import { program } from "commander";
+import * as fs from "node:fs/promises";
+
+//*** TODO ***
+// * Format results
+// * Add optional flags
+
+program
+  .name("wc")
+  .description("word, line and byte count")
+  .argument("<paths...>", "The file path(s) to process");
+
+program.parse();
+
+try {
+  const filePaths = program.args;
+  const results = {};
+
+  for (const filePath of filePaths) {
+    const file = await fs.open(filePath);
+    const stats = await fs.stat(filePath);
+
+    const count = { lines: 0, words: 0, bytes: stats.size };
+
+    try {
+      for await (const line of file.readLines()) {
+        count.lines++;
+        count.words += line.trim().split(/\s+/).length;
+      }
+    } finally {
+      await file.close();
+    }
+
+    results[filePath] = count;
+  }
+  console.log(results);
+} catch (err) {
+  console.error(err.message);
+}

From fafe5fd78bdf69cfdf32c1ebf2e2a1d34985d2e1 Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 07:35:59 +0000
Subject: [PATCH 08/11] feat(wc): format results into table with total counts
 for multiple files

---
 implement-shell-tools/wc/wc.js | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/implement-shell-tools/wc/wc.js b/implement-shell-tools/wc/wc.js
index 30dd2607e..9c822618d 100644
--- a/implement-shell-tools/wc/wc.js
+++ b/implement-shell-tools/wc/wc.js
@@ -33,7 +33,18 @@ try {
 
     results[filePath] = count;
   }
-  console.log(results);
+
+  if (filePaths.length > 1) {
+    const total = { lines: 0, words: 0, bytes: 0 };
+    for (const file of Object.values(results)) {
+      total.lines += file.lines;
+      total.words += file.words;
+      total.bytes += file.bytes;
+    }
+    results["total"] = total;
+  }
+
+  console.table(results);
 } catch (err) {
   console.error(err.message);
 }

From 0071dc4100cef86012954c1ae2a70f100d0386ff Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 07:56:06 +0000
Subject: [PATCH 09/11] feat(wc): add optional flags for line, word, and byte
 counting

---
 implement-shell-tools/wc/wc.js | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/implement-shell-tools/wc/wc.js b/implement-shell-tools/wc/wc.js
index 9c822618d..428e3337c 100644
--- a/implement-shell-tools/wc/wc.js
+++ b/implement-shell-tools/wc/wc.js
@@ -1,14 +1,22 @@
 import { program } from "commander";
 import * as fs from "node:fs/promises";
 
-//*** TODO ***
-// * Format results
-// * Add optional flags
-
 program
   .name("wc")
   .description("word, line and byte count")
-  .argument("<paths...>", "The file path(s) to process");
+  .argument("<paths...>", "The file path(s) to process.")
+  .option(
+    "-l, --lines",
+    "The number of lines in each input file is written to the standard output.",
+  )
+  .option(
+    "-w, --words",
+    "The number of words in each input file is written to the standard output.",
+  )
+  .option(
+    "-c --bytes",
+    "The number of bytes in each input file is written to the standard output.",
+  );
 
 program.parse();
 
@@ -19,7 +27,6 @@ try {
   for (const filePath of filePaths) {
     const file = await fs.open(filePath);
     const stats = await fs.stat(filePath);
-
     const count = { lines: 0, words: 0, bytes: stats.size };
 
     try {
@@ -30,7 +37,6 @@ try {
     } finally {
       await file.close();
     }
-
     results[filePath] = count;
   }
 
@@ -44,7 +50,13 @@ try {
     results["total"] = total;
   }
 
-  console.table(results);
+  const options = program.opts();
+  const noOptionsProvided = !Object.keys(options).length;
+  const selectedOptionKeys = [...Object.keys(options)];
+
+  noOptionsProvided
+    ? console.table(results)
+    : console.table(results, selectedOptionKeys);
 } catch (err) {
   console.error(err.message);
 }

From b9817fc3b9d93292df5f7e7f3e8307a1e4ae1fad Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 07:56:45 +0000
Subject: [PATCH 10/11] fix(wc): prevent counting empty lines as words

---
 implement-shell-tools/wc/wc.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/implement-shell-tools/wc/wc.js b/implement-shell-tools/wc/wc.js
index 428e3337c..a10798e32 100644
--- a/implement-shell-tools/wc/wc.js
+++ b/implement-shell-tools/wc/wc.js
@@ -32,7 +32,10 @@ try {
     try {
       for await (const line of file.readLines()) {
         count.lines++;
-        count.words += line.trim().split(/\s+/).length;
+        const trimmed = line.trim();
+        if (trimmed.length > 0) {
+          count.words += trimmed.split(/\s+/).length;
+        }
       }
     } finally {
       await file.close();

From 3f81d49dcc86757edc4cef828b07f18f03848e53 Mon Sep 17 00:00:00 2001
From: Jak R-S <176810031+jakr-s@users.noreply.github.com>
Date: Fri, 13 Mar 2026 10:42:03 +0000
Subject: [PATCH 11/11] feat(ls): support multiple file paths and improve
 visibility filtering

---
 implement-shell-tools/ls/ls.js | 51 ++++++++++++++++++++++++++++------
 1 file changed, 42 insertions(+), 9 deletions(-)

diff --git a/implement-shell-tools/ls/ls.js b/implement-shell-tools/ls/ls.js
index 3a45b8c1c..3034da06d 100644
--- a/implement-shell-tools/ls/ls.js
+++ b/implement-shell-tools/ls/ls.js
@@ -5,7 +5,7 @@ program
   .name("ls")
   .description("List directory contents")
   .argument(
-    "[path]",
+    "[paths...]",
     "The file path to process (defaults to current directory)",
   )
   .option("-a", "Include directory entries whose names begin with a dot ('.').")
@@ -14,20 +14,53 @@ program
 program.parse();
 
 try {
+  let filePaths = program.args;
+  if (!filePaths || filePaths.length === 0) {
+    filePaths = ["."];
+  }
+
   const options = program.opts();
-  const [filePathArg] = program.args;
+  const includeHidden = Boolean(options.a);
+  const onePerLine = Boolean(options["1"]);
+
+  const result = { files: [], dirs: {} };
+
+  for (const filePath of filePaths) {
+    const stats = await fs.stat(filePath);
+    if (stats.isFile()) result.files.push(filePath);
+    if (stats.isDirectory()) {
+      result.dirs[filePath] = await fs.readdir(filePath);
+    }
+  }
 
-  const filePath = filePathArg || process.cwd();
-  let files = await fs.readdir(filePath);
+  const filterHidden = (files) => files.filter((file) => !file.startsWith("."));
 
-  if (!options.a) files = files.filter((file) => !file.startsWith("."));
+  const getVisibleEntries = (files) =>
+    includeHidden ? files : filterHidden(files);
 
-  if (options["1"]) {
-    for (const file of files) {
-      console.log(file);
+  const formatEntries = (files) => {
+    if (files.length === 0) return;
+    console.log(files.join(onePerLine ? "\n" : "\t"));
+  };
+
+  result.files = getVisibleEntries(result.files);
+
+  if (filePaths.length === 1) {
+    let entries = [...result.files];
+
+    for (const [dir, contents] of Object.entries(result.dirs)) {
+      const filtered = getVisibleEntries(contents);
+      entries = entries.concat(filtered);
     }
+    formatEntries(entries);
   } else {
-    console.log(...files);
+    formatEntries(result.files);
+
+    for (const [dir, contents] of Object.entries(result.dirs)) {
+      console.log("\n" + dir + ":");
+      const filtered = getVisibleEntries(contents);
+      formatEntries(filtered);
+    }
   }
 } catch (err) {
   console.error(err.message);