London | SDC-Nov-25 | Emiliano Uruena | Sprint 2 | Shell-Pipelines

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

shell-pipelines/ls-grep/script-01.sh

@@ -2,5 +2,7 @@
 
 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.
+# 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]'

shell-pipelines/ls-grep/script-02.sh

@@ -2,5 +2,7 @@
 
 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.
+# 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]' 

shell-pipelines/ls-grep/script-03.sh

@@ -2,5 +2,7 @@
 
 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.
+# 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]*$'  

shell-pipelines/ls-grep/script-04.sh

@@ -2,5 +2,7 @@
 
 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.
+# 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 -c '^[A-Z][^A-Z]*$'

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 -k1 scores-table.txt

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 -k3rn scores-table.txt

shell-pipelines/sort-uniq-head-tail/script-03.sh

@@ -3,8 +3,10 @@
 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 lines for the three players with the highest first score, in descending order.
+# TODO: Write a command to output scores-table.txt, 
+#qwith shows the lines for the three players with the highest first score, in descending order.
 # Your output should be:
 # Basia London 22 9 6
 # Piotr Glasgow 15 2 25 11 8
 # Chandra Birmingham 12 6
+sort -k3rn scores-table.txt | head -n 3

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 -k3rn scores-table.txt | head -n 2 | tail -1 

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 

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.
+awk '{print $1}' events.txt | sort | uniq -c

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.
+awk '{print $3}' events-with-timestamps.txt | tail -n +2 | sort | uniq -c

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 '!' '.'

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 '!' '.' | tr 'yzYZ' 'zyZY'