sed for substitution in scripts in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to replace 'apple' with 'orange' in the file 'fruits.txt'.

Bash Scripting

sed '[1]' fruits.txt

Drag options to blanks, or click blank then click option'

As/apple/orange/g

Bd/apple/orange/g

Cr/apple/orange/g

Dx/apple/orange/g

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'r' instead of 's' for substitution.

Forgetting the 'g' flag to replace all occurrences.

Using incorrect command letters like 'd' or 'x'.

The 's' command in sed is used for substitution. 's/apple/orange/g' replaces all occurrences of 'apple' with 'orange'.

2fill in blank

medium

Complete the code to replace only the first occurrence of 'cat' with 'dog' in each line of 'pets.txt'.

Bash Scripting

sed '[1]' pets.txt

Drag options to blanks, or click blank then click option'

As/cat/dog/g

Bs/cat/dog/1

Cs/cat/dog/

Ds/cat/dog/2

Attempts:

3 left

💡 Hint

Common Mistakes

Adding 'g' flag replaces all occurrences, not just the first.

Using numbers like '/1' or '/2' which are not valid flags here.

Without the 'g' flag, sed replaces only the first occurrence per line. So 's/cat/dog/' replaces the first 'cat' with 'dog'.

3fill in blank

hard

Fix the error in the sed command to replace 'blue' with 'red' in 'colors.txt'.

Bash Scripting

sed '[1]' colors.txt

Drag options to blanks, or click blank then click option'

As/blue/red

Bs/blue/red/g

Cs/blue/red/g;

Ds/blue/red/g//

Attempts:

3 left

💡 Hint

Common Mistakes

Adding a semicolon at the end causes syntax error.

Adding extra slashes after 'g' causes errors.

Omitting the 'g' flag replaces only first occurrence.

The correct sed substitution command is 's/blue/red/g' without extra characters. It replaces all 'blue' with 'red'.

4fill in blank

hard

Fill both blanks to create a sed command that replaces 'dog' with 'cat' only on lines containing 'pet'.

Bash Scripting

sed -n '/[1]/ s/[2]/cat/gp' animals.txt

Drag options to blanks, or click blank then click option'

Apet

Bdog

Ccat

Danimal

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'cat' as the pattern to match lines instead of 'pet'.

Replacing 'cat' with 'dog' instead of the other way around.

Omitting the 'p' flag so lines are not printed.

The command '/pet/ s/dog/cat/gp' means: on lines matching 'pet', substitute 'dog' with 'cat' globally and print those lines.

5fill in blank

hard

Fill all three blanks to create a sed command that replaces 'apple' with 'banana' only on lines containing 'fruit' and saves output to 'new.txt'.

Bash Scripting

sed -n '/[1]/ s/[2]/[3]/gp' fruits.txt > new.txt

Drag options to blanks, or click blank then click option'

Afruit

Bapple

Cbanana

Dorange

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong pattern to match lines.

Swapping 'apple' and 'banana' in substitution.

Forgetting to redirect output to 'new.txt'.

The command '/fruit/ s/apple/banana/gp' means: on lines with 'fruit', replace 'apple' with 'banana' globally and print those lines. Redirect output to 'new.txt'.