diff --git a/number-systems/README.md b/number-systems/README.md deleted file mode 100644 index 77a3bde9..00000000 --- a/number-systems/README.md +++ /dev/null @@ -1,65 +0,0 @@ -Do not use any tools or programming to solve these problems. Work it out yourself by hand, and fill in the answers. - -Do not convert any binary numbers to decimal when solving a question unless the question explicitly tells you to. - -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: - -Convert the binary number 101101 to decimal: -Answer: - -Which is larger: 1000 or 0111? -Answer: - -Which is larger: 00100 or 01011? -Answer: - -What is 10101 + 01010? -Answer: - -What is 10001 + 10001? -Answer: - -What's the largest number you can store with 4 bits, if you want to be able to represent the number 0? -Answer: - -How many bits would you need in order to store the numbers between 0 and 255 inclusive? -Answer: - -How many bits would you need in order to store the numbers between 0 and 3 inclusive? -Answer: - -How many bits would you need in order to store the numbers between 0 and 1000 inclusive? -Answer: - -How can you test if a binary number is a power of two (e.g. 1, 2, 4, 8, 16, ...)? -Answer: - -Convert the decimal number 14 to hex. -Answer: - -Convert the decimal number 386 to hex. -Answer: - -Convert the hex number 386 to decimal. -Answer: - -Convert the hex number B to decimal. -Answer: - -If reading the byte 0x21 as a number, what decimal number would it mean? -Answer: - -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: - -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: diff --git a/shell-pipelines/ls-grep/script-01.sh b/shell-pipelines/ls-grep/script-01.sh index 8c7d968a..ddbda172 100755 --- a/shell-pipelines/ls-grep/script-01.sh +++ b/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]' \ 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 16f5f71d..f0d2dd51 100755 --- a/shell-pipelines/ls-grep/script-02.sh +++ b/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]' \ 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 a302ab03..8569b3ba 100755 --- a/shell-pipelines/ls-grep/script-03.sh +++ b/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]*$' \ No newline at end of file diff --git a/shell-pipelines/ls-grep/script-04.sh b/shell-pipelines/ls-grep/script-04.sh index c000b7e3..48731144 100755 --- a/shell-pipelines/ls-grep/script-04.sh +++ b/shell-pipelines/ls-grep/script-04.sh @@ -2,5 +2,7 @@ set -euo pipefail -# TODO: Write a command to count the number of files in the sample-files directory whose name starts with an upper case letter and doesn't contain any other upper case letters. +# TODO: Write a command to count the number of files in the sample-files directory +#whose name starts with an upper case letter and doesn't contain any other upper case letters. # Your output should be the number 7. +ls sample-files | grep -c '^[A-Z][^A-Z]*$' \ 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 171e1f98..db1efc26 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 -k1 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 29c3c252..e38bf38d 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 -k3rn 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 bcbaf342..ea32ded3 100755 --- a/shell-pipelines/sort-uniq-head-tail/script-03.sh +++ b/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 \ 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 65a5cfba..07f6bc96 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 -k3rn scores-table.txt | head -n 2 | tail -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 a93cd9f9..cf8e0ac0 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 715c7ae5..609c2f85 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. +awk '{print $1}' events.txt | sort | 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 7fd07e1f..830ce81a 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. +awk '{print $3}' events-with-timestamps.txt | tail -n +2 | 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 8bb0211e..6bd4576a 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 '!' '.' \ No newline at end of file diff --git a/shell-pipelines/tr/script-02.sh b/shell-pipelines/tr/script-02.sh index cf3a503a..667cbcca 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 '!' '.' | tr 'yzYZ' 'zyZY' \ No newline at end of file