diff --git a/implement-shell-tools/cat/cat.js b/implement-shell-tools/cat/cat.js
new file mode 100644
index 000000000..dcd7e09ba
--- /dev/null
+++ b/implement-shell-tools/cat/cat.js
@@ -0,0 +1,35 @@
+import { program } from 'commander'
+import process from 'process'
+import fs from 'fs'
+
+// const argv = process.argv[4]
+// const data = fs.readFileSync(`sample-files/${argv}`, 'utf-8')
+
+program
+  .command('cat <file>')
+  .description('Output file content')
+  .option('-a, --all', 'Output all content')
+  .option('-n, --line', 'Output each line with number')
+  .option('-b, --nonempty', 'Output total lines not empty')
+  .action((file, options) => {
+    const data = fs.readFileSync(`sample-files/${file}`, 'utf-8').split('\n')
+    if (options.all) {
+      console.log(data.join())
+    }
+    if (options.line) {
+      for (let i = 0; i < data.length; i++) {
+        console.log(`${i} - ${data[i]}`)
+      }
+    }
+    if (options.nonempty) {
+      let totalline = 0
+      data.forEach((line) => {
+        if (line.length != 0) {
+          totalline++
+        }
+      })
+      console.log(totalline)
+    }
+  })
+
+program.parse()
diff --git a/implement-shell-tools/cat/package-lock.json b/implement-shell-tools/cat/package-lock.json
new file mode 100644
index 000000000..737542646
--- /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": "^14.0.3"
+      }
+    },
+    "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..5d63dc09d
--- /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",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "type": "module",
+  "dependencies": {
+    "commander": "^14.0.3"
+  }
+}
diff --git a/implement-shell-tools/ls/ls.js b/implement-shell-tools/ls/ls.js
new file mode 100644
index 000000000..c5f440ae2
--- /dev/null
+++ b/implement-shell-tools/ls/ls.js
@@ -0,0 +1,22 @@
+import { program } from 'commander'
+import process from 'process'
+import fs from 'fs'
+program
+  .command('ls')
+  .description('Output available files on directory')
+  .option('-a, --all', 'Output all files')
+  .option('-1, --line', 'List one file per line')
+  .action((options) => {
+    const contents = fs.readdirSync(process.cwd(), { withFileTypes: true })
+
+    if (options.all) {
+      contents.forEach((content) => {
+        console.log(content.name)
+      })
+    }
+    if (options.line) {
+      console.log(contents[0].name)
+    }
+  })
+
+program.parse()
diff --git a/implement-shell-tools/ls/package-lock.json b/implement-shell-tools/ls/package-lock.json
new file mode 100644
index 000000000..74bc88d5b
--- /dev/null
+++ b/implement-shell-tools/ls/package-lock.json
@@ -0,0 +1,25 @@
+{
+  "name": "ls",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "ls",
+      "version": "1.0.0",
+      "license": "ISC",
+      "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..43e0a50d8
--- /dev/null
+++ b/implement-shell-tools/ls/package.json
@@ -0,0 +1,16 @@
+{
+  "name": "ls",
+  "version": "1.0.0",
+  "description": "You should already be familiar with the `ls` command line tool.",
+  "main": "ls.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "type": "module",
+  "dependencies": {
+    "commander": "^14.0.3"
+  }
+}
diff --git a/implement-shell-tools/wc/package-lock.json b/implement-shell-tools/wc/package-lock.json
new file mode 100644
index 000000000..c659e11e8
--- /dev/null
+++ b/implement-shell-tools/wc/package-lock.json
@@ -0,0 +1,90 @@
+{
+  "name": "wc",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "wc",
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "buffer": "^6.0.3",
+        "commander": "^14.0.3"
+      }
+    },
+    "node_modules/base64-js": {
+      "version": "1.5.1",
+      "resolved": "https://registry.npmjs.org/base64-js/-/base64-js-1.5.1.tgz",
+      "integrity": "sha512-AKpaYlHn8t4SVbOHCy+b5+KKgvR4vrsD8vbvrbiQJps7fKDTkjkDry6ji0rUJjC0kzbNePLwzxq8iypo41qeWA==",
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/feross"
+        },
+        {
+          "type": "patreon",
+          "url": "https://www.patreon.com/feross"
+        },
+        {
+          "type": "consulting",
+          "url": "https://feross.org/support"
+        }
+      ],
+      "license": "MIT"
+    },
+    "node_modules/buffer": {
+      "version": "6.0.3",
+      "resolved": "https://registry.npmjs.org/buffer/-/buffer-6.0.3.tgz",
+      "integrity": "sha512-FTiCpNxtwiZZHEZbcbTIcZjERVICn9yq/pDFkTl95/AxzD1naBctN7YO68riM/gLSDY7sdrMby8hofADYuuqOA==",
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/feross"
+        },
+        {
+          "type": "patreon",
+          "url": "https://www.patreon.com/feross"
+        },
+        {
+          "type": "consulting",
+          "url": "https://feross.org/support"
+        }
+      ],
+      "license": "MIT",
+      "dependencies": {
+        "base64-js": "^1.3.1",
+        "ieee754": "^1.2.1"
+      }
+    },
+    "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"
+      }
+    },
+    "node_modules/ieee754": {
+      "version": "1.2.1",
+      "resolved": "https://registry.npmjs.org/ieee754/-/ieee754-1.2.1.tgz",
+      "integrity": "sha512-dcyqhDvX1C46lXZcVqCpK+FtMRQVdIMN6/Df5js2zouUsqG7I6sFxitIC+7KYK29KdXOLHdu9zL4sFnoVQnqaA==",
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/feross"
+        },
+        {
+          "type": "patreon",
+          "url": "https://www.patreon.com/feross"
+        },
+        {
+          "type": "consulting",
+          "url": "https://feross.org/support"
+        }
+      ],
+      "license": "BSD-3-Clause"
+    }
+  }
+}
diff --git a/implement-shell-tools/wc/package.json b/implement-shell-tools/wc/package.json
new file mode 100644
index 000000000..85fa9a7b4
--- /dev/null
+++ b/implement-shell-tools/wc/package.json
@@ -0,0 +1,17 @@
+{
+  "name": "wc",
+  "version": "1.0.0",
+  "description": "You should already be familiar with the `wc` command line tool.",
+  "main": "wc.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "type": "module",
+  "dependencies": {
+    "buffer": "^6.0.3",
+    "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..d5176846d
--- /dev/null
+++ b/implement-shell-tools/wc/wc.js
@@ -0,0 +1,28 @@
+import { program } from 'commander'
+import fs from 'fs'
+import { Buffer } from 'buffer'
+import process from 'process'
+program
+  .command('wc <file>')
+  .description('File word counts')
+  .option('-l, --line', 'print the newline counts')
+  .option('-w, --count', 'print the word counts')
+  .option('-c, --bytes', 'print the bytes counts')
+  .action((file, options) => {
+    const content = fs.readFileSync(`sample-files/${file}`, 'utf-8')
+    if (options.line) {
+      console.log(content.split('\n').length)
+    }
+    if (options.bytes) {
+      console.log(Buffer.from(content).toString('hex'))
+    }
+    if (options.count) {
+      console.log(content.split(' ').length)
+    }
+    if (options.line && file == '*') {
+      const files = fs.readdirSync('sample-files/', { withFileTypes: true })
+      console.log(files)
+    }
+  })
+
+program.parse()
diff --git a/individual-shell-tools/awk/script-01.sh b/individual-shell-tools/awk/script-01.sh
index 8db4390af..c251968be 100755
--- a/individual-shell-tools/awk/script-01.sh
+++ b/individual-shell-tools/awk/script-01.sh
@@ -2,5 +2,6 @@
 
 set -euo pipefail
 
+awk '{print $1}' scores-table.txt
 # TODO: Write a command to output just the names of each player in `scores-table.txt`.
 # Your output should contain 6 lines, each with just one word on it.
diff --git a/individual-shell-tools/awk/script-02.sh b/individual-shell-tools/awk/script-02.sh
index 5956be9bd..fe8557ad1 100755
--- a/individual-shell-tools/awk/script-02.sh
+++ b/individual-shell-tools/awk/script-02.sh
@@ -2,5 +2,6 @@
 
 set -euo pipefail
 
+awk '{print $1,$2}' scores-table.txt
 # TODO: Write a command to output the names of each player, as well as their city.
 # Your output should contain 6 lines, each with two words on it, separated by a space.
diff --git a/individual-shell-tools/awk/script-03.sh b/individual-shell-tools/awk/script-03.sh
index af7c6e8b9..2f4511a83 100755
--- a/individual-shell-tools/awk/script-03.sh
+++ b/individual-shell-tools/awk/script-03.sh
@@ -2,6 +2,7 @@
 
 set -euo pipefail
 
+awk '{print $1,$3}' scores-table.txt
 # TODO: Write a command to output just the names of each player along with the score from their first attempt.
 # Your output should contain 6 lines, each with one word and one number on it.
 # The first line should be "Ahmed 1".
diff --git a/individual-shell-tools/awk/script-04.sh b/individual-shell-tools/awk/script-04.sh
index bf15703c7..b34630ab8 100755
--- a/individual-shell-tools/awk/script-04.sh
+++ b/individual-shell-tools/awk/script-04.sh
@@ -2,6 +2,7 @@
 
 set -euo pipefail
 
+awk '$2 == "London"{print $1,$5}' scores-table.txt
 # TODO: Write a command to output just the names of each player in London along with the score from their last attempt.
 # Your output should contain 3 lines, each with one word and one number on it.
 # The first line should be "Ahmed 4".
diff --git a/individual-shell-tools/awk/script-05.sh b/individual-shell-tools/awk/script-05.sh
index d1680cb02..bc6095442 100755
--- a/individual-shell-tools/awk/script-05.sh
+++ b/individual-shell-tools/awk/script-05.sh
@@ -2,6 +2,8 @@
 
 set -euo pipefail
 
+awk '($3 > 0) {attempt++} ($4 > 0) {attempt++} ($5 > 0) {attempt++} ($6 > 0) {attempt++} ($7 > 0) {attempt++} {print $1,attempt} attempt=0' scores-table.txt
+
 # TODO: Write a command to output just the names of each player along with the number of times they've played the game.
 # Your output should contain 6 lines, each with one word and one number on it.
 # The first line should be "Ahmed 3".
diff --git a/individual-shell-tools/awk/script-06-stretch.sh b/individual-shell-tools/awk/script-06-stretch.sh
index 0201e6378..f0a714ed1 100755
--- a/individual-shell-tools/awk/script-06-stretch.sh
+++ b/individual-shell-tools/awk/script-06-stretch.sh
@@ -3,6 +3,6 @@
 set -euo pipefail
 
 # NOTE: This is a stretch exercise - it is optional.
-
+awk '{total += $3} END {print total}' scores-table.txt
 # TODO: Write a command to output the total of adding together all players' first scores.
 # Your output should be exactly the number 54.
diff --git a/individual-shell-tools/cat/script-01.sh b/individual-shell-tools/cat/script-01.sh
index c85053e0f..682b379b6 100755
--- a/individual-shell-tools/cat/script-01.sh
+++ b/individual-shell-tools/cat/script-01.sh
@@ -3,4 +3,5 @@
 set -euo pipefail
 
 # TODO: Write a command to output the contents of the helper-1.txt file inside the helper-files directory to the terminal.
+cat ../helper-files/helper-1.txt
 # The output of this command should be "Once upon a time...".
diff --git a/individual-shell-tools/cat/script-02.sh b/individual-shell-tools/cat/script-02.sh
index 01bbd5eab..e0d70e235 100755
--- a/individual-shell-tools/cat/script-02.sh
+++ b/individual-shell-tools/cat/script-02.sh
@@ -11,3 +11,4 @@ set -euo pipefail
 # It looked delicious.
 # I was tempted to take a bite of it.
 # But this seemed like a bad idea...
+cat "../helper-files/helper-1.txt" "../helper-files/helper-2.txt" "../helper-files/helper-3.txt"
\ No newline at end of file
diff --git a/individual-shell-tools/cat/script-03.sh b/individual-shell-tools/cat/script-03.sh
index 37573b0c1..e4c6d99f6 100755
--- a/individual-shell-tools/cat/script-03.sh
+++ b/individual-shell-tools/cat/script-03.sh
@@ -9,3 +9,4 @@ set -euo pipefail
 # 1 It looked delicious.
 # 2 I was tempted to take a bite of it.
 # 3 But this seemed like a bad idea...
+cat -n ../helper-files/helper-3.txt
\ No newline at end of file
diff --git a/individual-shell-tools/grep/script-01.sh b/individual-shell-tools/grep/script-01.sh
index fb05f42f2..72ed5638b 100755
--- a/individual-shell-tools/grep/script-01.sh
+++ b/individual-shell-tools/grep/script-01.sh
@@ -2,5 +2,6 @@
 
 set -euo pipefail
 
+grep "" dialogue.txt
 # TODO: Write a command to output every line in dialogue.txt said by the Doctor.
 # The output should contain 6 lines.
diff --git a/individual-shell-tools/grep/script-02.sh b/individual-shell-tools/grep/script-02.sh
index df6f85640..e38d0cb56 100755
--- a/individual-shell-tools/grep/script-02.sh
+++ b/individual-shell-tools/grep/script-02.sh
@@ -2,5 +2,6 @@
 
 set -euo pipefail
 
+grep -F "Doctor" dialogue.txt
 # TODO: Write a command to output every line in dialogue.txt that contains the word Doctor (regardless of case).
 # The output should contain 9 lines.
diff --git a/individual-shell-tools/grep/script-03.sh b/individual-shell-tools/grep/script-03.sh
index 5383fe578..21138258a 100755
--- a/individual-shell-tools/grep/script-03.sh
+++ b/individual-shell-tools/grep/script-03.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output the number of lines in dialogue.txt that contain the word Doctor (regardless of case).
 # The output should be exactly the number 9.
+grep -ci "Doctor" dialogue.txt 
\ No newline at end of file
diff --git a/individual-shell-tools/grep/script-04.sh b/individual-shell-tools/grep/script-04.sh
index 80ee04776..392ff8d8f 100755
--- a/individual-shell-tools/grep/script-04.sh
+++ b/individual-shell-tools/grep/script-04.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output every line in dialogue.txt that does not contain the word "Hello" (regardless of case).
 # The output should contain 10 lines.
+grep -vi "Hello" dialogue.txt
\ No newline at end of file
diff --git a/individual-shell-tools/grep/script-05.sh b/individual-shell-tools/grep/script-05.sh
index 1eb538185..a7e28a473 100755
--- a/individual-shell-tools/grep/script-05.sh
+++ b/individual-shell-tools/grep/script-05.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output every line in dialogue.txt that contains the string "cure", as well as the line before that line.
 # The output should contain two pairs of two lines of text (with a separator between them).
+grep -B 1 "cure" dialogue.txt
\ No newline at end of file
diff --git a/individual-shell-tools/ls/script-01.sh b/individual-shell-tools/ls/script-01.sh
index 241b62f5e..044af3619 100755
--- a/individual-shell-tools/ls/script-01.sh
+++ b/individual-shell-tools/ls/script-01.sh
@@ -12,4 +12,5 @@ if [[ "${script_dir}" != "$(pwd)" ]]; then
 fi
 
 # TODO: Write a command to list the files and folders in this directory.
+ls
 # The output should be a list of names including child-directory, script-01.sh, script-02.sh, and more.
diff --git a/individual-shell-tools/ls/script-02.sh b/individual-shell-tools/ls/script-02.sh
index d0a5a10f4..5fecd71f1 100755
--- a/individual-shell-tools/ls/script-02.sh
+++ b/individual-shell-tools/ls/script-02.sh
@@ -3,4 +3,5 @@
 set -euo pipefail
 
 # TODO: Write a command which lists all of the files in the directory named child-directory.
+ls child-directory/
 # The output should be a list of names: helper-1.txt, helper-2.txt, helper-3.txt.
diff --git a/individual-shell-tools/ls/script-03.sh b/individual-shell-tools/ls/script-03.sh
index 781216d21..4ccbb560a 100755
--- a/individual-shell-tools/ls/script-03.sh
+++ b/individual-shell-tools/ls/script-03.sh
@@ -4,4 +4,5 @@ set -euo pipefail
 
 # TODO: Write a command which _recursively_ lists all of the files and folders in this directory _and_ all of the files inside those folders.
 # The output should be a list of names including: child-directory, script-01.sh, helper-1.txt (and more).
+ls -R
 # The formatting of the output doesn't matter.
diff --git a/individual-shell-tools/ls/script-04.sh b/individual-shell-tools/ls/script-04.sh
index 72f3817b3..8b8c3f534 100755
--- a/individual-shell-tools/ls/script-04.sh
+++ b/individual-shell-tools/ls/script-04.sh
@@ -15,9 +15,10 @@ echo "First exercise (sorted newest to oldest):"
 
 # TODO: Write a command which lists the files in the child-directory directory, one per line, sorted so that the most recently modified file is first.
 # The output should be a list of names in this order, one per line: helper-3.txt, helper-1.txt, helper-2.txt.
-
+ls -t child-directory
 
 echo "Second exercise (sorted oldest to newest):"
 
+ls -tr child-directory
 # TODO: Write a command which does the same as above, but sorted in the opposite order (oldest first).
 # The output should be a list of names in this order, one per line: helper-2.txt, helper-1.txt, helper-3.txt.
diff --git a/individual-shell-tools/sed/script-01.sh b/individual-shell-tools/sed/script-01.sh
index d592970fc..0c2fad10f 100755
--- a/individual-shell-tools/sed/script-01.sh
+++ b/individual-shell-tools/sed/script-01.sh
@@ -5,3 +5,4 @@ set -euo pipefail
 # TODO: Write a command to output input.txt with all occurrences of the letter `i` replaced with `I`.
 # The output should contain 11 lines.
 # The first line of the output should be: "ThIs Is a sample fIle for experImentIng wIth sed.".
+sed 's/i/I' input.txt
diff --git a/jq/scores.json b/jq/scores.json
index d5f62bf7a..1daea2144 100644
--- a/jq/scores.json
+++ b/jq/scores.json
@@ -1 +1,8 @@
-[{"name": "Ahmed", "city": "London", "scores": [1, 10, 4]}, {"name": "Basia", "city": "London", "scores": [22, 9, 6]}, {"name": "Mehmet", "city": "Birmingham", "scores": [3, 12, 17]}, {"name": "Leila", "city": "London", "scores": [1]}, {"name": "Piotr", "city": "Glasgow", "scores": [15, 2, 25, 11, 8]}, {"name": "Chandra", "city": "Birmingham", "scores": [12, 6]}]
+[
+  { "name": "Ahmed", "city": "London", "scores": [1, 10, 4] },
+  { "name": "Basia", "city": "London", "scores": [22, 9, 6] },
+  { "name": "Mehmet", "city": "Birmingham", "scores": [3, 12, 17] },
+  { "name": "Leila", "city": "London", "scores": [1] },
+  { "name": "Piotr", "city": "Glasgow", "scores": [15, 2, 25, 11, 8] },
+  { "name": "Chandra", "city": "Birmingham", "scores": [12, 6] }
+]
diff --git a/jq/script-01.sh b/jq/script-01.sh
index 95827f688..efc9479b2 100755
--- a/jq/script-01.sh
+++ b/jq/script-01.sh
@@ -4,4 +4,5 @@ set -euo pipefail
 
 # The input for this script is the person.json file.
 # TODO: Write a command to output the name of the person.
+jq '.name' person.json
 # Your output should be exactly the string "Selma", but should not contain any quote characters.
diff --git a/jq/script-02.sh b/jq/script-02.sh
index 21544d67b..421db5a62 100755
--- a/jq/script-02.sh
+++ b/jq/script-02.sh
@@ -4,4 +4,5 @@ set -euo pipefail
 
 # The input for this script is the person.json file.
 # TODO: Write a command to output the address of the person, all on one line, with a comma between each line.
+jq -c '.address | join(", ")' person.json
 # Your output should be exactly the string "35 Fashion Street, London, E1 6PX", but should not contain any quote characters.
diff --git a/jq/script-03.sh b/jq/script-03.sh
index 3566f03ba..ad448aff3 100755
--- a/jq/script-03.sh
+++ b/jq/script-03.sh
@@ -4,4 +4,5 @@ set -euo pipefail
 
 # The input for this script is the person.json file.
 # TODO: Write a command to output the name of the person, then a comma, then their profession.
+jq  '[.name, .profession] | join(", ")' person.json
 # Your output should be exactly the string "Selma, Software Engineer", but should not contain any quote characters.
diff --git a/jq/script-04.sh b/jq/script-04.sh
index 015997e18..a3254cee2 100755
--- a/jq/script-04.sh
+++ b/jq/script-04.sh
@@ -4,5 +4,6 @@ set -euo pipefail
 
 # The input for this script is the scores.json file.
 # TODO: Write a command to output just the names of each player, one per line.
+jq '.[].name' scores.json
 # Your output should contain 6 lines, each with just one word on it.
 # Your output should not contain any quote characters.
diff --git a/number-systems/README.md b/number-systems/README.md
index 77a3bde94..3efe1280a 100644
--- a/number-systems/README.md
+++ b/number-systems/README.md
@@ -6,60 +6,61 @@ The goal of these exercises is for you to gain an intuition for binary numbers.
 
 Convert the decimal number 14 to binary.
 Answer:
-
+0001 0100
 Convert the binary number 101101 to decimal:
 Answer:
-
+45
 Which is larger: 1000 or 0111?
 Answer:
-
+1000
 Which is larger: 00100 or 01011?
 Answer:
-
+01011
 What is 10101 + 01010?
 Answer:
-
+11111
 What is 10001 + 10001?
 Answer:
-
+100010
 What's the largest number you can store with 4 bits, if you want to be able to represent the number 0?
 Answer:
-
+15
 How many bits would you need in order to store the numbers between 0 and 255 inclusive?
 Answer:
-
+8 bits
 How many bits would you need in order to store the numbers between 0 and 3 inclusive?
 Answer:
-
+2 bits
 How many bits would you need in order to store the numbers between 0 and 1000 inclusive?
 Answer:
-
+10 bits
 How can you test if a binary number is a power of two (e.g. 1, 2, 4, 8, 16, ...)?
 Answer:
-
+Binary number should have at least 1 bit set to 1
 Convert the decimal number 14 to hex.
 Answer:
-
+E
 Convert the decimal number 386 to hex.
 Answer:
-
+182
 Convert the hex number 386 to decimal.
 Answer:
-
+902
 Convert the hex number B to decimal.
 Answer:
-
+11
 If reading the byte 0x21 as a number, what decimal number would it mean?
 Answer:
-
+33
 If reading the byte 0x21 as an ASCII character, what character would it mean?
 Answer:
-
+!
 If reading the byte 0x21 as a greyscale colour, as described in "Approaches for Representing Colors and Images", what colour would it mean?
 Answer:
-
+dark grey
 If reading the bytes 0xAA00FF as an RGB colour, as described in "Approaches for Representing Colors and Images", what colour would it mean?
 Answer:
 
 If reading the bytes 0xAA00FF as a sequence of three one-byte decimal numbers, what decimal numbers would they be?
 Answer:
+(170, 0, 255)
diff --git a/shell-pipelines/ls-grep/script-01.sh b/shell-pipelines/ls-grep/script-01.sh
index 8c7d968a2..11b640a34 100755
--- a/shell-pipelines/ls-grep/script-01.sh
+++ b/shell-pipelines/ls-grep/script-01.sh
@@ -3,4 +3,5 @@
 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.
+ls sample-files | grep '[A-Z]'
 # Your output should contain 11 files.
diff --git a/shell-pipelines/ls-grep/script-02.sh b/shell-pipelines/ls-grep/script-02.sh
index 16f5f71d9..8e73df07b 100755
--- a/shell-pipelines/ls-grep/script-02.sh
+++ b/shell-pipelines/ls-grep/script-02.sh
@@ -3,4 +3,5 @@
 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.
+ls sample-files | grep '^[A-Z]'
 # Your output should contain 10 files.
diff --git a/shell-pipelines/ls-grep/script-03.sh b/shell-pipelines/ls-grep/script-03.sh
index a302ab036..e836be84e 100755
--- a/shell-pipelines/ls-grep/script-03.sh
+++ b/shell-pipelines/ls-grep/script-03.sh
@@ -3,4 +3,5 @@
 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.
+ls sample-files | grep '^[A-Z][^A-Z]*$'
 # Your output should contain 7 files.
diff --git a/shell-pipelines/ls-grep/script-04.sh b/shell-pipelines/ls-grep/script-04.sh
index c000b7e3b..5ae6ab961 100755
--- a/shell-pipelines/ls-grep/script-04.sh
+++ b/shell-pipelines/ls-grep/script-04.sh
@@ -3,4 +3,5 @@
 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.
+ls sample-files | grep -c '^[A-Z][^A-Z]*$'
 # Your output should be the number 7.
diff --git a/shell-pipelines/sort-uniq-head-tail/script-01.sh b/shell-pipelines/sort-uniq-head-tail/script-01.sh
index 171e1f989..c43bc7e78 100755
--- a/shell-pipelines/sort-uniq-head-tail/script-01.sh
+++ b/shell-pipelines/sort-uniq-head-tail/script-01.sh
@@ -4,4 +4,5 @@ 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.
+sort scores-table.txt 
 # 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".
diff --git a/shell-pipelines/sort-uniq-head-tail/script-02.sh b/shell-pipelines/sort-uniq-head-tail/script-02.sh
index 29c3c2524..b65564747 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 -nr 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..e0576a164 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 -k3nr 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..344612f86 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 -k3nr 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..6bfeb53c2 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 -u events.txt
\ 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..a1f6faf26 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 --group
diff --git a/shell-pipelines/sort-uniq-head-tail/script-07.sh b/shell-pipelines/sort-uniq-head-tail/script-07.sh
index 7fd07e1ff..91442b64a 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.
+sort events.txt | uniq --group
\ No newline at end of file
diff --git a/shell-pipelines/tr/script-01.sh b/shell-pipelines/tr/script-01.sh
index 8bb0211e9..75c3ed25f 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 (.).
+cat text.txt | tr '!' '.'
diff --git a/shell-pipelines/tr/script-02.sh b/shell-pipelines/tr/script-02.sh
index cf3a503a2..261497f1b 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).
+cat text.txt | tr 'Z' 'z' | tr 'Y' 'y' | tr 'z' 'Z' | tr 'y' 'Y'