diff --git a/implement-shell-tools/cat/cat.js b/implement-shell-tools/cat/cat.js
new file mode 100644
index 000000000..91b05a806
--- /dev/null
+++ b/implement-shell-tools/cat/cat.js
@@ -0,0 +1,16 @@
+import { program } from "commander";
+import { promises as fs } from "node:fs";
+
+program.argument("<files...>").parse();
+
+for (const file of program.args) {
+  const stat = await fs.stat(file);
+
+  if (stat.isDirectory()) {
+    console.error(`cat: ${file}: Is a directory`);
+    continue;
+  }
+
+  const content = await fs.readFile(file, "utf-8");
+  process.stdout.write(content);
+}
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..402b2a4e9
--- /dev/null
+++ b/implement-shell-tools/cat/package.json
@@ -0,0 +1,6 @@
+{
+  "dependencies": {
+    "commander": "^14.0.3"
+  },
+  "type": "module"
+}
diff --git a/shell-pipelines/ls-grep/script-01.sh b/shell-pipelines/ls-grep/script-01.sh
index 8c7d968a2..2530df5cf 100755
--- a/shell-pipelines/ls-grep/script-01.sh
+++ b/shell-pipelines/ls-grep/script-01.sh
@@ -4,3 +4,4 @@ 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]'
\ No newline at end of file
diff --git a/shell-pipelines/ls-grep/script-02.sh b/shell-pipelines/ls-grep/script-02.sh
index 16f5f71d9..90eb3f2bf 100755
--- a/shell-pipelines/ls-grep/script-02.sh
+++ b/shell-pipelines/ls-grep/script-02.sh
@@ -4,3 +4,4 @@ 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]'
\ No newline at end of file
diff --git a/shell-pipelines/ls-grep/script-03.sh b/shell-pipelines/ls-grep/script-03.sh
index a302ab036..5c7a491be 100755
--- a/shell-pipelines/ls-grep/script-03.sh
+++ b/shell-pipelines/ls-grep/script-03.sh
@@ -4,3 +4,4 @@ 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 '^[A-Z][a-z]*$'
diff --git a/shell-pipelines/ls-grep/script-04.sh b/shell-pipelines/ls-grep/script-04.sh
index c000b7e3b..e165a5c5f 100755
--- a/shell-pipelines/ls-grep/script-04.sh
+++ b/shell-pipelines/ls-grep/script-04.sh
@@ -4,3 +4,4 @@ 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 '^[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..1db218dbb 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-01.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-01.sh
@@ -5,3 +5,4 @@ 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
\ No newline at end of file
diff --git a/shell-pipelines/sort-uniq-head-tail/script-02.sh b/shell-pipelines/sort-uniq-head-tail/script-02.sh
index 29c3c2524..f32b03b63 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-02.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-02.sh
@@ -5,3 +5,4 @@ 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 -k3,3nr scores-table.txt
\ No newline at end of file
diff --git a/shell-pipelines/sort-uniq-head-tail/script-03.sh b/shell-pipelines/sort-uniq-head-tail/script-03.sh
index bcbaf3420..4b5cf8b99 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-03.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-03.sh
@@ -8,3 +8,4 @@ set -euo pipefail
 # Basia London 22 9 6
 # Piotr Glasgow 15 2 25 11 8
 # Chandra Birmingham 12 6
+sort -k3,3nr 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..02b7b95fc 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-04.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-04.sh
@@ -5,3 +5,4 @@ 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 -k3,3nr scores-table.txt | head -n 2 | tail -n 1
\ No newline at end of file
diff --git a/shell-pipelines/sort-uniq-head-tail/script-05.sh b/shell-pipelines/sort-uniq-head-tail/script-05.sh
index a93cd9f9d..bdc16e1c8 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-05.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-05.sh
@@ -6,3 +6,4 @@ 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
\ No newline at end of file
diff --git a/shell-pipelines/sort-uniq-head-tail/script-06.sh b/shell-pipelines/sort-uniq-head-tail/script-06.sh
index 715c7ae5c..930f1d70c 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-06.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-06.sh
@@ -5,3 +5,4 @@ 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.
+sort events.txt | uniq -c
\ No newline at end of file
diff --git a/shell-pipelines/sort-uniq-head-tail/script-07.sh b/shell-pipelines/sort-uniq-head-tail/script-07.sh
index 7fd07e1ff..0850c7743 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-07.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-07.sh
@@ -6,3 +6,4 @@ 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.
+cut -d' ' -f2 events-with-timestamps.txt | sort | uniq -c
\ No newline at end of file
diff --git a/shell-pipelines/tr/script-01.sh b/shell-pipelines/tr/script-01.sh
index 8bb0211e9..3553c5aa5 100755
--- a/shell-pipelines/tr/script-01.sh
+++ b/shell-pipelines/tr/script-01.sh
@@ -6,3 +6,4 @@ 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
\ No newline at end of file
diff --git a/shell-pipelines/tr/script-02.sh b/shell-pipelines/tr/script-02.sh
index cf3a503a2..a5250f788 100755
--- a/shell-pipelines/tr/script-02.sh
+++ b/shell-pipelines/tr/script-02.sh
@@ -7,3 +7,4 @@ 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
\ No newline at end of file