diff --git a/.gitignore b/.gitignore
index 3c3629e64..274d04915 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 node_modules
+.venv
\ No newline at end of file
diff --git a/implement-shell-tools/.gitignore b/implement-shell-tools/.gitignore
new file mode 100644
index 000000000..e6e0086b4
--- /dev/null
+++ b/implement-shell-tools/.gitignore
@@ -0,0 +1,7 @@
+# Ignore node_modules everywhere
+**/node_modules/
+
+#ignore logs, environment files.
+*.log
+.env
+dist/
diff --git a/implement-shell-tools/cat/cat.js b/implement-shell-tools/cat/cat.js
new file mode 100644
index 000000000..624b885ac
--- /dev/null
+++ b/implement-shell-tools/cat/cat.js
@@ -0,0 +1,75 @@
+import { program } from "commander";
+import { promises as fs } from "node:fs";
+import process from "node:process";
+
+program
+  .name("my-cat")
+  .description("Reads and prints one or more files, optionally numbering lines continuously")
+  .argument("<paths...>", "One or more file paths")
+  .option("-n, --number", "Number all output lines", false)
+  .option("-b, --number-nonblank", "Number non-empty output lines", false);
+
+program.parse();
+
+const filePaths = program.args;
+const options = program.opts();
+
+const numberNonBlank = options.numberNonblank;
+const numberAll = options.number && !numberNonBlank;
+
+(async () => {
+  let lineNumber = 1; 
+  
+  //  calculate total lines if using -n
+  let totalLines = 0;
+  if (numberAll) {
+    for (const path of filePaths) {
+      try {
+        const content = await fs.readFile(path, "utf-8");
+        const lines = content.split("\n");
+
+        totalLines += content.endsWith("\n") ? lines.length - 1 : lines.length;
+      } catch (err) {
+        console.error(`Error reading file "${path}": ${err.message}`);
+        process.exit(1);
+      }
+    }
+  }
+
+  for (const path of filePaths) {
+    try {
+      const content = await fs.readFile(path, "utf-8");
+      const lines = content.split("\n");
+
+      if (numberNonBlank) {
+        const maxDigits = String(lines.filter(line => line.trim() !== '').length).length;
+
+        for (const line of lines) {
+          if (line.trim() === '') {
+            process.stdout.write("\n");
+          } else {
+            const numStr = String(lineNumber++).padStart(maxDigits, " ");
+            process.stdout.write(`${numStr}\t${line}\n`);
+          }
+        }
+      } else if (numberAll) {
+        const maxDigits = totalLines > 0 ? String(totalLines).length : 1;
+
+
+        for (const line of lines) {
+          const numStr = String(lineNumber++).padStart(maxDigits, " ");
+          process.stdout.write(`${numStr}\t${line}\n`);
+        }
+      } else {
+        // no numbering, just print file content as is
+        process.stdout.write(content);
+        if (!content.endsWith("\n")) {
+          process.stdout.write("\n"); // ensure newline after file if missing
+        }
+      }
+    } catch (err) {
+      console.error(`Error reading file "${path}": ${err.message}`);
+      process.exit(1);
+    }
+  }
+})();
diff --git a/implement-shell-tools/cat/package-lock.json b/implement-shell-tools/cat/package-lock.json
new file mode 100644
index 000000000..7c3bcb9aa
--- /dev/null
+++ b/implement-shell-tools/cat/package-lock.json
@@ -0,0 +1,25 @@
+{
+  "name": "cat",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "cat",
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "commander": "^14.0.0"
+      }
+    },
+    "node_modules/commander": {
+      "version": "14.0.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-14.0.0.tgz",
+      "integrity": "sha512-2uM9rYjPvyq39NwLRqaiLtWHyDC1FvryJDa2ATTVims5YAS4PupsEQsDvP14FqhFr0P49CYDugi59xaxJlTXRA==",
+      "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..4ef36c57d
--- /dev/null
+++ b/implement-shell-tools/cat/package.json
@@ -0,0 +1,16 @@
+{
+  "name": "cat",
+  "version": "1.0.0",
+  "description": "You should already be familiar with the `cat` command line tool.",
+  "main": "cat.js",
+  "type": "module",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "commander": "^14.0.0"
+  }
+}
diff --git a/implement-shell-tools/ls/ls.js b/implement-shell-tools/ls/ls.js
new file mode 100644
index 000000000..8925dd7d6
--- /dev/null
+++ b/implement-shell-tools/ls/ls.js
@@ -0,0 +1,69 @@
+import { program } from "commander";
+import { promises as fs } from "node:fs";
+import path from "node:path";
+
+program
+  .name("my-ls")
+  .description("List files in a directory (simplified ls implementation)")
+  .argument("[paths...]", "One or more file or directory paths")
+  .option("-l, --longList", "Long listing format", false)
+  .option("-a, --all", "Include hidden files", false);
+
+program.parse();
+
+// CHANGED: apply default value for paths here if none are provided
+let filePaths = program.args.length > 0 ? program.args : ['.']; 
+const options = program.opts();
+
+const showLong = options.longList;
+const showAll = options.all;
+
+// Helper function to convert mode to rwxrwxrwx string
+function formatPermissions(mode, isDir) {
+  const typeChar = isDir ? 'd' : '-';
+  const perms = [0, 1, 2].map(i => {
+    const shift = 6 - i * 3;
+    const r = (mode >> shift) & 4 ? 'r' : '-';
+    const w = (mode >> shift) & 2 ? 'w' : '-';
+    const x = (mode >> shift) & 1 ? 'x' : '-';
+    return r + w + x;
+  }).join('');
+  return typeChar + perms;
+}
+
+(async () => {
+  for (const inputPath of filePaths) {
+    try {
+      const stat = await fs.stat(inputPath);
+
+      if (stat.isFile()) {
+        if (showLong) {
+          const perms = formatPermissions(stat.mode, false);
+          console.log(`${perms}  ${stat.size.toString().padStart(6)}  ${inputPath}`);
+        } else {
+          console.log(inputPath);
+        }
+      } else if (stat.isDirectory()) {
+        const entries = await fs.readdir(inputPath, { withFileTypes: true });
+
+        const filtered = showAll
+          ? entries
+          : entries.filter((entry) => !entry.name.startsWith("."));
+
+        for (const entry of filtered) {
+          const fullPath = path.join(inputPath, entry.name);
+          const entryStat = await fs.stat(fullPath);
+          if (showLong) {
+            const perms = formatPermissions(entryStat.mode, entryStat.isDirectory());
+            console.log(`${perms}  ${entryStat.size.toString().padStart(6)}  ${entry.name}`);
+          } else {
+            console.log(entry.name);
+          }
+        }
+      }
+    } catch (err) {
+      console.error(`Error reading "${inputPath}": ${err.message}`);
+      process.exit(1);
+    }
+  }
+})();
diff --git a/implement-shell-tools/ls/package-lock.json b/implement-shell-tools/ls/package-lock.json
new file mode 100644
index 000000000..bff254485
--- /dev/null
+++ b/implement-shell-tools/ls/package-lock.json
@@ -0,0 +1,21 @@
+{
+  "name": "ls",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "dependencies": {
+        "commander": "^14.0.0"
+      }
+    },
+    "node_modules/commander": {
+      "version": "14.0.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-14.0.0.tgz",
+      "integrity": "sha512-2uM9rYjPvyq39NwLRqaiLtWHyDC1FvryJDa2ATTVims5YAS4PupsEQsDvP14FqhFr0P49CYDugi59xaxJlTXRA==",
+      "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..1ca3878d3
--- /dev/null
+++ b/implement-shell-tools/ls/package.json
@@ -0,0 +1,17 @@
+{
+  "dependencies": {
+    "commander": "^14.0.0"
+  },
+  "name": "ls",
+  "version": "1.0.0",
+  "description": "You should already be familiar with the `ls` command line tool.",
+  "main": "ls.js",
+  "type": "module",
+  "devDependencies": {},
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC"
+}
diff --git a/implement-shell-tools/wc/package-lock.json b/implement-shell-tools/wc/package-lock.json
new file mode 100644
index 000000000..b3a3f4f8d
--- /dev/null
+++ b/implement-shell-tools/wc/package-lock.json
@@ -0,0 +1,21 @@
+{
+  "name": "wc",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "dependencies": {
+        "commander": "^14.0.0"
+      }
+    },
+    "node_modules/commander": {
+      "version": "14.0.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-14.0.0.tgz",
+      "integrity": "sha512-2uM9rYjPvyq39NwLRqaiLtWHyDC1FvryJDa2ATTVims5YAS4PupsEQsDvP14FqhFr0P49CYDugi59xaxJlTXRA==",
+      "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..68279600c
--- /dev/null
+++ b/implement-shell-tools/wc/package.json
@@ -0,0 +1,6 @@
+{
+  "type": "module",
+  "dependencies": {
+    "commander": "^14.0.0"
+  }
+}
diff --git a/implement-shell-tools/wc/wc.js b/implement-shell-tools/wc/wc.js
new file mode 100644
index 000000000..4d5588abe
--- /dev/null
+++ b/implement-shell-tools/wc/wc.js
@@ -0,0 +1,74 @@
+import { program } from "commander";
+import { promises as fs } from "node:fs";
+import { stat } from "node:fs/promises";
+
+program
+  .name("my-wc")
+  .description("Simplified implementation of wc")
+  .argument("[paths...]", "One or more file or directory paths")
+  .option("-l, --line", "Count lines")
+  .option("-w, --word", "Count words")
+  .option("-c, --character", "Count characters");
+
+program.parse();
+
+const filePaths = program.args.length > 0 ? program.args : ['.'];
+const options = program.opts();
+
+const countContent = (content) => {
+  const lines = content.split('\n').length;
+  const words = content.trim().split(/\s+/).filter(Boolean).length;
+  const characters = content.length;
+  return { lines, words, characters };
+};
+
+const total = {
+  lines: 0,
+  words: 0,
+  characters: 0
+};
+
+//Output formatting function
+function formatOutput(counts, label, options) {
+  const { lines, words, characters } = counts;
+  const showAll = !options.line && !options.word && !options.character;
+
+  const parts = [];
+
+  if (options.line || showAll) parts.push(lines.toString().padStart(8));
+  if (options.word || showAll) parts.push(words.toString().padStart(8));
+  if (options.character || showAll) parts.push(characters.toString().padStart(8));
+
+  parts.push(label);
+  return parts.join(" ");
+}
+
+(async () => {
+  let fileCount = 0;
+
+  for (const inputPath of filePaths) {
+    try {
+      const stats = await stat(inputPath);
+      if (stats.isDirectory()) {
+        console.log(`${inputPath} is a directory. Skipping.`);
+        continue;
+      }
+
+      const content = await fs.readFile(inputPath, "utf-8");
+      const counts = countContent(content);
+
+      total.lines += counts.lines;
+      total.words += counts.words;
+      total.characters += counts.characters;
+      fileCount++;
+
+      console.log(formatOutput(counts, inputPath, options));
+    } catch (err) {
+      console.error(`Error reading "${inputPath}": ${err.message}`);
+    }
+  }
+
+  if (fileCount > 1) {
+    console.log(formatOutput(total, "total", options));
+  }
+})();
diff --git a/shell-pipelines/ls-grep/script-01.sh b/shell-pipelines/ls-grep/script-01.sh
index 8c7d968a2..87c191290 100755
--- a/shell-pipelines/ls-grep/script-01.sh
+++ b/shell-pipelines/ls-grep/script-01.sh
@@ -4,3 +4,5 @@ set -euo pipefail
 
 # TODO: Write a command to output the names of the files in the sample-files directory whose name contains at least one upper case letter.
 # Your output should contain 11 files.
+
+ls sample-files | grep '[A-Z]'
diff --git a/shell-pipelines/ls-grep/script-02.sh b/shell-pipelines/ls-grep/script-02.sh
index 16f5f71d9..bf4e06cdd 100755
--- a/shell-pipelines/ls-grep/script-02.sh
+++ b/shell-pipelines/ls-grep/script-02.sh
@@ -4,3 +4,6 @@ set -euo pipefail
 
 # TODO: Write a command to output the names of the files in the sample-files directory whose name starts with an upper case letter.
 # Your output should contain 10 files.
+
+ls sample-files | grep '^[A-Z]'
+
diff --git a/shell-pipelines/ls-grep/script-03.sh b/shell-pipelines/ls-grep/script-03.sh
index a302ab036..efcd84613 100755
--- a/shell-pipelines/ls-grep/script-03.sh
+++ b/shell-pipelines/ls-grep/script-03.sh
@@ -4,3 +4,5 @@ set -euo pipefail
 
 # TODO: Write a command to output the names of the files in the sample-files directory whose name starts with an upper case letter and doesn't contain any other upper case letters.
 # Your output should contain 7 files.
+
+ls sample-files | grep -E '^[A-Z][^A-Z]*$'
diff --git a/shell-pipelines/ls-grep/script-04.sh b/shell-pipelines/ls-grep/script-04.sh
index c000b7e3b..2da3786f2 100755
--- a/shell-pipelines/ls-grep/script-04.sh
+++ b/shell-pipelines/ls-grep/script-04.sh
@@ -4,3 +4,5 @@ set -euo pipefail
 
 # TODO: Write a command to count the number of files in the sample-files directory whose name starts with an upper case letter and doesn't contain any other upper case letters.
 # Your output should be the number 7.
+
+ls sample-files | grep -E '^[A-Z][^A-Z]*$' | wc -l
\ No newline at end of file
diff --git a/shell-pipelines/sort-uniq-head-tail/script-01.sh b/shell-pipelines/sort-uniq-head-tail/script-01.sh
index 171e1f989..038386659 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-01.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-01.sh
@@ -5,3 +5,5 @@ set -euo pipefail
 # The input for this script is the scores-table.txt file.
 # TODO: Write a command to output scores-table.txt, with lines sorted by the person's name.
 # The first line of your output should be "Ahmed London 1 10 4" (with no quotes). And the third line should be "Chandra Birmingham 12 6".
+
+sort scores-table.txt
diff --git a/shell-pipelines/sort-uniq-head-tail/script-02.sh b/shell-pipelines/sort-uniq-head-tail/script-02.sh
index 29c3c2524..3853cc614 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-02.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-02.sh
@@ -5,3 +5,6 @@ set -euo pipefail
 # The input for this script is the scores-table.txt file.
 # TODO: Write a command to output scores-table.txt, with lines sorted by the person's first score, descending.
 # The first line of your output should be "Basia London 22 9 6" (with no quotes).
+
+
+sort -k3,3 -nr scores-table.txt
diff --git a/shell-pipelines/sort-uniq-head-tail/script-03.sh b/shell-pipelines/sort-uniq-head-tail/script-03.sh
index bcbaf3420..3fb062dc1 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-03.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-03.sh
@@ -8,3 +8,5 @@ set -euo pipefail
 # Basia London 22 9 6
 # Piotr Glasgow 15 2 25 11 8
 # Chandra Birmingham 12 6
+
+sort -k3,3 -nr scores-table.txt | head -n 3
\ No newline at end of file
diff --git a/shell-pipelines/sort-uniq-head-tail/script-04.sh b/shell-pipelines/sort-uniq-head-tail/script-04.sh
index 65a5cfba8..6809dfe7d 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-04.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-04.sh
@@ -5,3 +5,5 @@ set -euo pipefail
 # The input for this script is the scores-table.txt file.
 # TODO: Write a command to output scores-table.txt, with shows the line for the player whose first score was the second highest.
 # Your output should be: "Piotr Glasgow 15 2 25 11 8" (without quotes).
+
+sort -k3,3 -nr scores-table.txt | head -n 2 | tail -n 1
diff --git a/shell-pipelines/sort-uniq-head-tail/script-05.sh b/shell-pipelines/sort-uniq-head-tail/script-05.sh
index a93cd9f9d..7bba7d19a 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-05.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-05.sh
@@ -6,3 +6,5 @@ set -euo pipefail
 # TODO: Write a command to show a list of all events that have happened, without duplication.
 # The order they're displayed doesn't matter, but we never want to see the same event listed twice.
 # Your output should contain 6 lines.
+
+sort events.txt | uniq
diff --git a/shell-pipelines/sort-uniq-head-tail/script-06.sh b/shell-pipelines/sort-uniq-head-tail/script-06.sh
index 715c7ae5c..4d8a50c5c 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-06.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-06.sh
@@ -5,3 +5,6 @@ set -euo pipefail
 # The input for this script is the events.txt file.
 # TODO: Write a command to show how many times anyone has entered and exited.
 # It should be clear from your script's output that there have been 5 Entry events and 4 Exit events.
+
+
+awk '{print $3}' events.txt | sort | uniq -c
diff --git a/shell-pipelines/sort-uniq-head-tail/script-07.sh b/shell-pipelines/sort-uniq-head-tail/script-07.sh
index 7fd07e1ff..23cc6c898 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-07.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-07.sh
@@ -6,3 +6,7 @@ set -euo pipefail
 # TODO: Write a command to show how many times anyone has entered and exited.
 # It should be clear from your script's output that there have been 5 Entry events and 4 Exit events.
 # The word "Event" should not appear in your script's output.
+
+
+awk '$3 == "Entry" || $3 == "Exit" {print $3}' events-with-timestamps.txt | sort | uniq -c
+
diff --git a/shell-pipelines/tr/script-01.sh b/shell-pipelines/tr/script-01.sh
index 8bb0211e9..b638ad8f6 100755
--- a/shell-pipelines/tr/script-01.sh
+++ b/shell-pipelines/tr/script-01.sh
@@ -6,3 +6,5 @@ set -euo pipefail
 # The author got feedback that they're using too many exclamation marks (!).
 #
 # TODO: Write a command to output the contents of text.txt with every exclamation mark (!) replaced with a full-stop (.).
+
+tr '!' '.' < text.txt
diff --git a/shell-pipelines/tr/script-02.sh b/shell-pipelines/tr/script-02.sh
index cf3a503a2..126177b90 100755
--- a/shell-pipelines/tr/script-02.sh
+++ b/shell-pipelines/tr/script-02.sh
@@ -7,3 +7,5 @@ set -euo pipefail
 # so every Y should be a Z, and every Z should be a Y!
 #
 # TODO: Write a command to output the contents of text.txt with every Y and Z swapped (both upper and lower case).
+
+tr 'yYzZ' 'zZyY' < text.txt