hamdiheb · hamdiheb · Mar 22, 2026 · Mar 22, 2026 · Mar 22, 2026 · Mar 22, 2026
diff --git 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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"
diff --git 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
diff --git 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
@@ -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
@@ -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 
diff --git 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
diff --git 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
diff --git 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
diff --git 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
diff --git 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
@@ -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
diff --git 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
@@ -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
diff --git 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
@@ -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'
Original file line number	Diff line number	Diff line change
Expand Up		@@ -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
Original file line number	Diff line number	Diff line change
Expand Up		@@ -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
-Original file line number
+Diff line change
@@ Expand Up / @@ -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.