From 8fb3596668d73582a9b07d2ec8443c837c73c5fd Mon Sep 17 00:00:00 2001
From: Emilianouz <135679131+Emilianouz@users.noreply.github.com>
Date: Tue, 11 Nov 2025 11:56:34 +0000
Subject: [PATCH 1/8] Numeric Systems: answers

---
 number-systems/README.md | 41 ++++++++++++++++++++--------------------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/number-systems/README.md b/number-systems/README.md
index 77a3bde94..322d053c6 100644
--- a/number-systems/README.md
+++ b/number-systems/README.md
@@ -5,61 +5,62 @@ Do not convert any binary numbers to decimal when solving a question unless the
 The goal of these exercises is for you to gain an intuition for binary numbers. Using tools to solve the problems defeats the point.
 
 Convert the decimal number 14 to binary.
-Answer:
+Answer: 1110
 
 Convert the binary number 101101 to decimal:
-Answer:
+Answer: 45
 
 Which is larger: 1000 or 0111?
-Answer:
+Answer: 1000
 
 Which is larger: 00100 or 01011?
-Answer:
+Answer: 01011
 
 What is 10101 + 01010?
-Answer:
+Answer:  11111
 
 What is 10001 + 10001?
-Answer:
+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:
+Answer: 1111 = 15 (largest representable number)
+        Number of possible values including 0 = 16
 
 How many bits would you need in order to store the numbers between 0 and 255 inclusive?
-Answer:
+Answer: 8 bits
 
 How many bits would you need in order to store the numbers between 0 and 3 inclusive?
-Answer:
+Answer: 2 bits => 00, 01, 10, 11
 
 How many bits would you need in order to store the numbers between 0 and 1000 inclusive?
-Answer:
+Answer: 10 bits
 
 How can you test if a binary number is a power of two (e.g. 1, 2, 4, 8, 16, ...)?
-Answer:
+Answer: Been a binary it would be 1 followed by 0s => 100, 10000, 10
 
 Convert the decimal number 14 to hex.
-Answer:
+Answer:0xE
 
 Convert the decimal number 386 to hex.
-Answer:
+Answer: 0x182
 
 Convert the hex number 386 to decimal.
-Answer:
+Answer: 902
 
 Convert the hex number B to decimal.
-Answer:
+Answer:11
 
 If reading the byte 0x21 as a number, what decimal number would it mean?
-Answer:
+Answer:33
 
 If reading the byte 0x21 as an ASCII character, what character would it mean?
-Answer:
+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:
+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:
+Answer:Purple (magenta)
 
 If reading the bytes 0xAA00FF as a sequence of three one-byte decimal numbers, what decimal numbers would they be?
-Answer:
+Answer: 170 0 255

From e7032b51ccea758ce169cfb25ad7910f0a1031b7 Mon Sep 17 00:00:00 2001
From: Emilianouz <135679131+Emilianouz@users.noreply.github.com>
Date: Tue, 11 Nov 2025 22:59:17 +0000
Subject: [PATCH 2/8] Exercises and command explanations for ls

---
 individual-shell-tools/ls/script-01.sh | 1 +
 individual-shell-tools/ls/script-02.sh | 1 +
 individual-shell-tools/ls/script-03.sh | 1 +
 individual-shell-tools/ls/script-04.sh | 3 ++-
 4 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/individual-shell-tools/ls/script-01.sh b/individual-shell-tools/ls/script-01.sh
index 241b62f5e..0641b0f3f 100755
--- a/individual-shell-tools/ls/script-01.sh
+++ b/individual-shell-tools/ls/script-01.sh
@@ -13,3 +13,4 @@ fi
 
 # TODO: Write a command to list the files and folders in this directory.
 # The output should be a list of names including child-directory, script-01.sh, script-02.sh, and more.
+ls
\ No newline at end of file
diff --git a/individual-shell-tools/ls/script-02.sh b/individual-shell-tools/ls/script-02.sh
index d0a5a10f4..e5054a9ee 100755
--- a/individual-shell-tools/ls/script-02.sh
+++ b/individual-shell-tools/ls/script-02.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command which lists all of the files in the directory named child-directory.
 # The output should be a list of names: helper-1.txt, helper-2.txt, helper-3.txt.
+ls child-directory 
\ No newline at end of file
diff --git a/individual-shell-tools/ls/script-03.sh b/individual-shell-tools/ls/script-03.sh
index 781216d21..7a1a1d315 100755
--- a/individual-shell-tools/ls/script-03.sh
+++ b/individual-shell-tools/ls/script-03.sh
@@ -5,3 +5,4 @@ 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).
 # The formatting of the output doesn't matter.
+ls -R
\ No newline at end of file
diff --git a/individual-shell-tools/ls/script-04.sh b/individual-shell-tools/ls/script-04.sh
index 72f3817b3..5b2f461da 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 -R -1 -t child-directory 
 
 echo "Second exercise (sorted oldest to newest):"
 
 # 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.
+ls -R -1 -t -r child-directory
\ No newline at end of file

From c1e3caf78106bb1914afc3655679a036b40e6bee Mon Sep 17 00:00:00 2001
From: Emilianouz <135679131+Emilianouz@users.noreply.github.com>
Date: Tue, 11 Nov 2025 23:01:00 +0000
Subject: [PATCH 3/8] Answers command cat

---
 individual-shell-tools/cat/script-01.sh | 1 +
 individual-shell-tools/cat/script-02.sh | 1 +
 individual-shell-tools/cat/script-03.sh | 1 +
 3 files changed, 3 insertions(+)

diff --git a/individual-shell-tools/cat/script-01.sh b/individual-shell-tools/cat/script-01.sh
index c85053e0f..2f0ac6d4e 100755
--- a/individual-shell-tools/cat/script-01.sh
+++ b/individual-shell-tools/cat/script-01.sh
@@ -4,3 +4,4 @@ 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.
 # The output of this command should be "Once upon a time...".
+cat helper-files/helper-1.txt
\ No newline at end of file
diff --git a/individual-shell-tools/cat/script-02.sh b/individual-shell-tools/cat/script-02.sh
index 01bbd5eab..df2d75327 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/*
\ 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..c5babeb8c 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

From 45b3af3464df3c5cf372ac523396ce93128b17e6 Mon Sep 17 00:00:00 2001
From: Emilianouz <135679131+Emilianouz@users.noreply.github.com>
Date: Tue, 11 Nov 2025 23:01:25 +0000
Subject: [PATCH 4/8] Answers command wc

---
 individual-shell-tools/wc/script-01.sh | 1 +
 individual-shell-tools/wc/script-02.sh | 1 +
 individual-shell-tools/wc/script-03.sh | 1 +
 3 files changed, 3 insertions(+)

diff --git a/individual-shell-tools/wc/script-01.sh b/individual-shell-tools/wc/script-01.sh
index c9dd6e5df..6e8ef4195 100755
--- a/individual-shell-tools/wc/script-01.sh
+++ b/individual-shell-tools/wc/script-01.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output the number of words in the file helper-files/helper-3.txt.
 # The output should include the number 19. The output should not include the number 92.
+wc -w helper-files/helper-3.txt
\ No newline at end of file
diff --git a/individual-shell-tools/wc/script-02.sh b/individual-shell-tools/wc/script-02.sh
index 8feeb1a62..cdd372b18 100755
--- a/individual-shell-tools/wc/script-02.sh
+++ b/individual-shell-tools/wc/script-02.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output the number of lines in the file helper-files/helper-3.txt.
 # The output should include the number 3. The output should not include the number 19.
+wc -l helper-files/helper-3.txt
\ No newline at end of file
diff --git a/individual-shell-tools/wc/script-03.sh b/individual-shell-tools/wc/script-03.sh
index 6b2e9d3d1..dae6bbf93 100755
--- a/individual-shell-tools/wc/script-03.sh
+++ b/individual-shell-tools/wc/script-03.sh
@@ -8,3 +8,4 @@ set -euo pipefail
 #        1       7      39 ../helper-files/helper-2.txt
 #        3      19      92 ../helper-files/helper-3.txt
 #        5      30     151 total
+wc helper-files/*
\ No newline at end of file

From d1a2b37035946a827f660f0c048d074d12f5bb18 Mon Sep 17 00:00:00 2001
From: Emilianouz <135679131+Emilianouz@users.noreply.github.com>
Date: Tue, 11 Nov 2025 23:02:05 +0000
Subject: [PATCH 5/8] Answers command grep

---
 individual-shell-tools/grep/script-01.sh | 1 +
 individual-shell-tools/grep/script-02.sh | 1 +
 individual-shell-tools/grep/script-03.sh | 1 +
 individual-shell-tools/grep/script-04.sh | 1 +
 individual-shell-tools/grep/script-05.sh | 1 +
 individual-shell-tools/grep/script-06.sh | 1 +
 individual-shell-tools/grep/script-07.sh | 1 +
 7 files changed, 7 insertions(+)

diff --git a/individual-shell-tools/grep/script-01.sh b/individual-shell-tools/grep/script-01.sh
index fb05f42f2..72cd51b58 100755
--- a/individual-shell-tools/grep/script-01.sh
+++ b/individual-shell-tools/grep/script-01.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output every line in dialogue.txt said by the Doctor.
 # The output should contain 6 lines.
+grep "^Doctor:" dialogue.txt
\ No newline at end of file
diff --git a/individual-shell-tools/grep/script-02.sh b/individual-shell-tools/grep/script-02.sh
index df6f85640..eb861e1fc 100755
--- a/individual-shell-tools/grep/script-02.sh
+++ b/individual-shell-tools/grep/script-02.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # 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.
+grep -i "doctor" dialogue.txt
\ No newline at end of file
diff --git a/individual-shell-tools/grep/script-03.sh b/individual-shell-tools/grep/script-03.sh
index 5383fe578..c55d1b941 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 -c -i "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..a76aea457 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 -v -i "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/grep/script-06.sh b/individual-shell-tools/grep/script-06.sh
index 5670e3b6c..79b6e5308 100755
--- a/individual-shell-tools/grep/script-06.sh
+++ b/individual-shell-tools/grep/script-06.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output the name of every `.txt` file in this directory which contains a line of dialogue said by the Doctor.
 # The output should contain two filenames.
+grep -l "^Doctor" *.txt 
\ No newline at end of file
diff --git a/individual-shell-tools/grep/script-07.sh b/individual-shell-tools/grep/script-07.sh
index 9670ebad9..4b287aa4f 100755
--- a/individual-shell-tools/grep/script-07.sh
+++ b/individual-shell-tools/grep/script-07.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output, for each `.txt` file in this directory, how many lines of dialogue the Doctor has.
 # The output should show that dialogue.txt contains 6 lines, dialogue-2.txt contains 2, and dialogue-3.txt contains 0.
+grep -c "^Doctor:" *.txt
\ No newline at end of file

From b07ab404190a42987e0bfdf2f24ef44ee40e9af3 Mon Sep 17 00:00:00 2001
From: Emilianouz <135679131+Emilianouz@users.noreply.github.com>
Date: Tue, 11 Nov 2025 23:02:27 +0000
Subject: [PATCH 6/8] Answers command sed

---
 individual-shell-tools/sed/script-01.sh | 1 +
 individual-shell-tools/sed/script-02.sh | 1 +
 individual-shell-tools/sed/script-03.sh | 1 +
 individual-shell-tools/sed/script-04.sh | 1 +
 individual-shell-tools/sed/script-06.sh | 1 +
 5 files changed, 5 insertions(+)

diff --git a/individual-shell-tools/sed/script-01.sh b/individual-shell-tools/sed/script-01.sh
index 3eba6fa4d..57faad5ba 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/g' input.txt
\ No newline at end of file
diff --git a/individual-shell-tools/sed/script-02.sh b/individual-shell-tools/sed/script-02.sh
index abdd64d06..d3f70b8ce 100755
--- a/individual-shell-tools/sed/script-02.sh
+++ b/individual-shell-tools/sed/script-02.sh
@@ -5,3 +5,4 @@ set -euo pipefail
 # TODO: Write a command to output input.txt with numbers removed.
 # The output should contain 11 lines.
 # Line 6 of the output should be " Alisha".
+sed 's/[0-9]//g' input.txt
\ No newline at end of file
diff --git a/individual-shell-tools/sed/script-03.sh b/individual-shell-tools/sed/script-03.sh
index dd284a296..02b29409e 100755
--- a/individual-shell-tools/sed/script-03.sh
+++ b/individual-shell-tools/sed/script-03.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output input.txt removing any line which contains a number.
 # The output should contain 6 lines.
+sed '/[0-9]/d' input.txt
\ No newline at end of file
diff --git a/individual-shell-tools/sed/script-04.sh b/individual-shell-tools/sed/script-04.sh
index 0052ac6c4..5638418ae 100755
--- a/individual-shell-tools/sed/script-04.sh
+++ b/individual-shell-tools/sed/script-04.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # TODO: Write a command to output input.txt replacing every occurrence of the string "We'll" with "We will".
 # The output should contain 11 lines.
+sed "s/We'll/We will/g" input.txt 
\ No newline at end of file
diff --git a/individual-shell-tools/sed/script-06.sh b/individual-shell-tools/sed/script-06.sh
index 0b9390170..4655f4588 100755
--- a/individual-shell-tools/sed/script-06.sh
+++ b/individual-shell-tools/sed/script-06.sh
@@ -8,3 +8,4 @@ set -euo pipefail
 # The output should contain 11 lines.
 # Line 3 should be "It contains many lines, and there are some things you may want to do with each of them.".
 # Line 11 should be "We also should remember, when we go shopping, to get 4 items: oranges, cheese, bread, olives.".
+sed 's/,\([^ ]\)/, \1/g' input.txt
\ No newline at end of file

From c636d2a88ed4ca1ea07eb73a7dc436db7d6892ed Mon Sep 17 00:00:00 2001
From: Emilianouz <135679131+Emilianouz@users.noreply.github.com>
Date: Tue, 11 Nov 2025 23:02:39 +0000
Subject: [PATCH 7/8] Answers command sed

---
 individual-shell-tools/sed/script-05.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/individual-shell-tools/sed/script-05.sh b/individual-shell-tools/sed/script-05.sh
index 2dcc91a0c..a84551d5c 100755
--- a/individual-shell-tools/sed/script-05.sh
+++ b/individual-shell-tools/sed/script-05.sh
@@ -6,3 +6,4 @@ set -euo pipefail
 # If a line starts with a number and a space, make the line instead end with a space and the number.
 # So line 6 which currently reads "37 Alisha" should instead read "Alisha 37".
 # The output should contain 11 lines.
+sed -E 's/^([0-9]+) (.*)$/\2 \1/' input.txt
\ No newline at end of file

From 3db650d1851dd94fcd7ce58e63b64bd6e7bbba7c Mon Sep 17 00:00:00 2001
From: Emilianouz <135679131+Emilianouz@users.noreply.github.com>
Date: Tue, 11 Nov 2025 23:02:58 +0000
Subject: [PATCH 8/8] Answers command awk

---
 individual-shell-tools/awk/script-01.sh         | 1 +
 individual-shell-tools/awk/script-02.sh         | 1 +
 individual-shell-tools/awk/script-03.sh         | 4 +++-
 individual-shell-tools/awk/script-04.sh         | 1 +
 individual-shell-tools/awk/script-05.sh         | 1 +
 individual-shell-tools/awk/script-06-stretch.sh | 1 +
 6 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/individual-shell-tools/awk/script-01.sh b/individual-shell-tools/awk/script-01.sh
index 8db4390af..824e4c58b 100755
--- a/individual-shell-tools/awk/script-01.sh
+++ b/individual-shell-tools/awk/script-01.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # 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.
+awk '{print $1}' scores-table.txt
\ No newline at end of file
diff --git a/individual-shell-tools/awk/script-02.sh b/individual-shell-tools/awk/script-02.sh
index 5956be9bd..f52195b03 100755
--- a/individual-shell-tools/awk/script-02.sh
+++ b/individual-shell-tools/awk/script-02.sh
@@ -4,3 +4,4 @@ set -euo pipefail
 
 # 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.
+awk '{print $1,$2}' scores-table.txt
\ No newline at end of file
diff --git a/individual-shell-tools/awk/script-03.sh b/individual-shell-tools/awk/script-03.sh
index af7c6e8b9..82266d8f1 100755
--- a/individual-shell-tools/awk/script-03.sh
+++ b/individual-shell-tools/awk/script-03.sh
@@ -2,6 +2,8 @@
 
 set -euo pipefail
 
-# TODO: Write a command to output just the names of each player along with the score from their first attempt.
+# 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".
+awk '{print $1,$3}' scores-table.txt 
\ No newline at end of file
diff --git a/individual-shell-tools/awk/script-04.sh b/individual-shell-tools/awk/script-04.sh
index bf15703c7..b58969157 100755
--- a/individual-shell-tools/awk/script-04.sh
+++ b/individual-shell-tools/awk/script-04.sh
@@ -5,3 +5,4 @@ set -euo pipefail
 # 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".
+awk '$2 == "London" {print $1,$NF}' scores-table.txt
\ No newline at end of file
diff --git a/individual-shell-tools/awk/script-05.sh b/individual-shell-tools/awk/script-05.sh
index d1680cb02..1ea440d4a 100755
--- a/individual-shell-tools/awk/script-05.sh
+++ b/individual-shell-tools/awk/script-05.sh
@@ -5,3 +5,4 @@ set -euo pipefail
 # 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".
+awk '{print $1,NF-2}' scores-table.txt 
\ No newline at end of file
diff --git a/individual-shell-tools/awk/script-06-stretch.sh b/individual-shell-tools/awk/script-06-stretch.sh
index 0201e6378..6a268bbeb 100755
--- a/individual-shell-tools/awk/script-06-stretch.sh
+++ b/individual-shell-tools/awk/script-06-stretch.sh
@@ -6,3 +6,4 @@ set -euo pipefail
 
 # TODO: Write a command to output the total of adding together all players' first scores.
 # Your output should be exactly the number 54.
+awk '{sum += $3} END {print sum}' scores-table.txt
\ No newline at end of file