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1 change: 1 addition & 0 deletions individual-shell-tools/cat/script-01.sh
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# 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
1 change: 1 addition & 0 deletions individual-shell-tools/cat/script-02.sh
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# It looked delicious.
# I was tempted to take a bite of it.
# But this seemed like a bad idea...
cat ../helper-files/*
1 change: 1 addition & 0 deletions individual-shell-tools/cat/script-03.sh
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# 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
1 change: 1 addition & 0 deletions individual-shell-tools/cat/script-04-stretch.sh
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# 3 It looked delicious.
# 4 I was tempted to take a bite of it.
# 5 But this seemed like a bad idea...
cat ../helper-files/* | nl
1 change: 1 addition & 0 deletions individual-shell-tools/ls/script-01.sh
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# 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
1 change: 1 addition & 0 deletions individual-shell-tools/ls/script-02.sh
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# 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
1 change: 1 addition & 0 deletions individual-shell-tools/ls/script-03.sh
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# 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
3 changes: 2 additions & 1 deletion individual-shell-tools/ls/script-04.sh
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Expand Up @@ -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 -1t ./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 -1tr ./child-directory
1 change: 1 addition & 0 deletions individual-shell-tools/wc/script-01.sh
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# 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
1 change: 1 addition & 0 deletions individual-shell-tools/wc/script-02.sh
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# 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
1 change: 1 addition & 0 deletions individual-shell-tools/wc/script-03.sh
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# 1 7 39 ../helper-files/helper-2.txt
# 3 19 92 ../helper-files/helper-3.txt
# 5 30 151 total
wc ../helper-files/*
40 changes: 20 additions & 20 deletions number-systems/README.md
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Expand Up @@ -5,61 +5,61 @@ 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: 0b1110

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: Signed numbers: 0b0111 = 7. Unsigned numbers: 0b1111 = 15

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

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: Power of two will have only 1 bit set to 1, and the rest of the bits set to zero. e.g 0b1000, 0b0100, 0b0010

Convert the decimal number 14 to hex.
Answer:
Answer: E

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

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
1 change: 1 addition & 0 deletions shell-pipelines/ls-grep/script-01.sh
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# 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]'
1 change: 1 addition & 0 deletions shell-pipelines/ls-grep/script-02.sh
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# 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]'
1 change: 1 addition & 0 deletions shell-pipelines/ls-grep/script-03.sh
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# 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]*$'
1 change: 1 addition & 0 deletions shell-pipelines/ls-grep/script-04.sh
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# TODO: Write a command to count the number of files in the sample-files directory whose name starts with an upper case letter and doesn't contain any other upper case letters.
# Your output should be the number 7.
ls ./sample-files | grep '^[A-Z][^A-Z]*$' | wc -l