export command in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of the export command?

You run the following commands in a Linux shell:

MYVAR=hello
export MYVAR
export

What will be part of the output when you run export?

Linux CLI

MYVAR=hello
export MYVAR
export

A Only the variable MYVAR=hello is shown

B A list of all exported environment variables including MYVAR=hello

C No output is shown

D An error message saying 'export: command not found'

💡 Hint

The export command without arguments lists all exported variables.

The export command without arguments prints all environment variables that are exported. Since MYVAR was exported, it will appear in the list with its value.

💻 Command Output

intermediate

What happens when you export a variable with spaces?

Consider the commands:

export MYVAR=hello world
export MYVAR

What will happen when you run these commands in a Linux shell?

Linux CLI

export MYVAR=hello world
export MYVAR

A MYVAR is unset

B MYVAR is set to 'hello world' correctly

C MYVAR is set to 'hello' and 'world' is treated as a separate command

D Syntax error because of the space in the value without quotes

💡 Hint

Spaces in variable values need quotes.

Without quotes, the shell treats 'world' as a separate command or argument, causing a syntax error.

🔧 Debug

advanced

Why does this export command not set the variable in the parent shell?

You run this command in your shell:

export MYVAR=hello

Then in a new terminal, you run:

echo $MYVAR

But it prints nothing. Why?

Linux CLI

export MYVAR=hello
# In a new terminal:
echo $MYVAR

A Because echo command is wrong

B Because MYVAR was not set correctly

C Because export only affects the current shell and its child processes, not new terminals

D Because export clears variables after the command finishes

💡 Hint

Think about how environment variables are inherited.

Environment variables set with export exist only in the current shell session and its children. New terminals start new shells without those variables.

🧠 Conceptual

advanced

What is the effect of 'export -n VAR' in Linux shell?

You have a variable VAR exported. What does the command export -n VAR do?

Linux CLI

export VAR=hello
export -n VAR

A It removes the export attribute, so VAR is no longer exported to child processes

B It sets VAR to an empty string

C It exports VAR with a new value '-n VAR'

D It causes a syntax error

💡 Hint

The -n option removes export status.

The export -n command removes the export attribute from the variable, so it remains in the shell but is not passed to child processes.

🚀 Application

expert

How to export multiple variables in one command correctly?

You want to export two variables VAR1 and VAR2 with values 'foo' and 'bar' in one command. Which command does this correctly?

A export VAR1=foo VAR2=bar

B export VAR1=foo; export VAR2=bar

C export VAR1=foo, VAR2=bar

D export VAR1=foo && VAR2=bar

💡 Hint

Multiple variables can be exported in one export command separated by spaces.

The export command accepts multiple variable assignments separated by spaces. Commas or && are not valid separators here.