String prefix removal (${var#pattern}) in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to remove the shortest prefix 'abc' from the variable.

Bash Scripting

result=${var[1]abc}

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

A##

B#

C%

D%%

Attempts:

3 left

💡 Hint

Common Mistakes

Using ## removes the longest prefix instead of the shortest.

Using % or %% removes suffixes, not prefixes.

The single # removes the shortest matching prefix pattern from the variable.

2fill in blank

medium

Complete the code to remove the shortest prefix matching any characters up to 'end'.

Bash Scripting

result=${var[1]*end}

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

A#

B%

C##

D%%

Attempts:

3 left

💡 Hint

Common Mistakes

Using ## removes the longest prefix, which may remove more than intended.

Using % or %% removes suffixes, not prefixes.

Using # with '*end' removes the shortest prefix ending with 'end'.

3fill in blank

hard

Fix the error in the code to remove the shortest prefix 'temp_' from the variable.

Bash Scripting

cleaned=${var[1]temp_}

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

A%%

B%

C#

D##

Attempts:

3 left

💡 Hint

Common Mistakes

Using % or %% tries to remove suffixes, causing no change.

Using ## removes the longest prefix, which may remove more than intended.

The single # removes the shortest prefix 'temp_' from the variable.

4fill in blank

hard

Fill both blanks to remove the shortest prefix matching 'log_' and assign to output.

Bash Scripting

output=$[1][2]log_}

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

Avar

B##

C#

Dfile

Attempts:

3 left

💡 Hint

Common Mistakes

Using ## removes the longest prefix, which is not correct here.

Using wrong variable names like 'file' causes errors.

Use 'var' as the variable name and '#' to remove the shortest prefix 'log_'.

5fill in blank

hard

Fill all three blanks to create a dictionary with keys as filenames without 'tmp_' prefix and values as their sizes.

Bash Scripting

declare -A sizes; for [3] in tmp_files; do sizes[[1]]=$(stat -c%s [2]); done

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

A${file#tmp_}

B$file

Cfile

D${file##tmp_}

Attempts:

3 left

💡 Hint

Common Mistakes

Using ${file##tmp_} removes the longest prefix, which may remove more than intended.

Using different variable names inconsistently causes errors.

Use '${file#tmp_}' to remove the shortest 'tmp_' prefix for keys, '$file' as the filename for stat, and 'file' as the loop variable.