Why scripts often process text in Bash Scripting - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print the first word of the line.

Bash Scripting

echo "Hello world" | cut -d ' ' -f [1]

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A1

B2

C0

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 as field number causes no output.

Using 2 or 3 extracts the second or third word, not the first.

The cut command with -f 1 extracts the first field (word) separated by space.

2fill in blank

medium

Complete the code to count lines containing the word 'error'.

Bash Scripting

grep 'error' logfile.txt | wc -l > [1]

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Aoutput.txt

Bresult.txt

Ccount.txt

Derrors.log

Attempts:

3 left

💡 Hint

Common Mistakes

Using a log file name may confuse output with input.

Not redirecting output causes no file to be created.

Redirecting output to count.txt saves the number of lines with 'error'.

3fill in blank

hard

Fix the error in the code to replace 'foo' with 'bar' in file.txt.

Bash Scripting

sed -i 's/[1]/bar/g' file.txt

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Abar

Bfoo

Cfile

Dtext

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping 'foo' and 'bar' reverses the replacement.

Using unrelated words causes no change.

The sed command replaces 'foo' with 'bar', so 'foo' must be the search pattern.

4fill in blank

hard

Fill both blanks to create a dictionary of word lengths for words longer than 3 letters.

Bash Scripting

declare -A lengths
for word in apple banana cat dog; do
  if [[ ${#word} [1] 3 ]]; then
    lengths[[2]]=${#word}
  fi
done

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A>

Bword

C<

Dlen

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > reverses the condition.

Using len instead of word as key causes errors.

We check if word length is greater than 3 and use the word as the key in the dictionary.

5fill in blank

hard

Fill all three blanks to filter lines containing 'error' and count unique occurrences.

Bash Scripting

grep [1] logfile.txt | sort | uniq -c | sort [2] -k1,1 | head -n [3]

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A'error'

B-nr

C5

D-r

Attempts:

3 left

💡 Hint

Common Mistakes

Using -r instead of -nr sorts incorrectly.

Not limiting head to 5 lines shows too many results.

We grep 'error', sort uniquely counting occurrences, sort numerically reverse, and show top 5.