Default values (${var:-default}) in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print the value of VAR or 'default' if VAR is empty or unset.

Bash Scripting

echo ${VAR[1]default}

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

A:=

B:-

C-

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' instead of ':-' which does not check for empty values.

Using ':=' which assigns the default value to VAR.

Using '+' which behaves differently.

The syntax ${VAR:-default} prints VAR if set and not empty; otherwise, it prints 'default'.

2fill in blank

medium

Complete the code to assign 'default' to VAR only if VAR is unset or empty.

Bash Scripting

VAR=[1]

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

A${VAR:-}

B${VAR:=}

C${VAR:-default}

D${VAR:=default}

Attempts:

3 left

💡 Hint

Common Mistakes

Using ':-' which only provides a default for output but does not assign.

Using empty default values which do nothing.

The '${VAR:=default}' syntax assigns 'default' to VAR if it is unset or empty.

3fill in blank

hard

Fix the error in the code to print 'default' if VAR is unset or empty.

Bash Scripting

echo ${VAR[1]default}

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

A:=

B-

C:-

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' which does not handle empty values.

Using ':=' which assigns instead of just printing.

The correct syntax is '${VAR:-default}' to print 'default' if VAR is unset or empty.

4fill in blank

hard

Fill both blanks to print VAR if set and not empty, else print 'default'.

Bash Scripting

echo $[1][2]default}

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

AVAR

B:-

C-

DVAR:-

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' instead of ':-' which ignores empty values.

Putting the operator before the variable name.

Use '${VAR:-default}' to print VAR if set and not empty, else 'default'.

5fill in blank

hard

Fill both blanks to assign 'default' to VAR only if VAR is unset or empty, then print VAR.

Bash Scripting

[1]={{BLANK_2}default
echo $}

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

AVAR

B${VAR:=

D}

Attempts:

3 left

💡 Hint

Common Mistakes

Not closing the brace in the assignment syntax.

Using ':-' instead of ':=' which does not assign.

The code assigns 'default' to VAR if unset or empty using '${VAR:=default}', then prints VAR.