Command structure (command, options, arguments) in Linux CLI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to list files in long format.

Linux CLI

ls [1]

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

A-l

B-a

C-h

D-r

Attempts:

3 left

💡 Hint

Common Mistakes

Using -a shows hidden files but not detailed info.

Using -h shows sizes in human-readable form but needs -l for details.

The -l option shows files in long listing format.

2fill in blank

medium

Complete the command to show all files including hidden ones.

Linux CLI

ls [1]

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

A-l

B-a

C-r

D-t

Attempts:

3 left

💡 Hint

Common Mistakes

Using -l shows details but not hidden files.

Using -r reverses order but does not show hidden files.

The -a option lists all files, including hidden files starting with a dot.

3fill in blank

hard

Fix the error in the command to copy file1 to file2.

Linux CLI

cp [1] file2

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

A-a

B-r

Cfile1

Dfile3

Attempts:

3 left

💡 Hint

Common Mistakes

Using options like -r when copying a single file causes errors.

Specifying wrong source filename.

The command copies file1 to file2. The source file must be specified without options.

4fill in blank

hard

Fill both blanks to find all .txt files in the current directory.

Linux CLI

find . [1] [2] '*.txt'

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

A-type f

B-name

C-iname

D-type d

Attempts:

3 left

💡 Hint

Common Mistakes

Using -type d finds directories, not files.

Using -iname matches case-insensitive but is not required here.

-type f limits results to files, and -name '*.txt' matches files ending with .txt.

5fill in blank

hard

Fill all three blanks to move all .log files to the logs directory.

Linux CLI

mv [1] [2] [3]

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

A-v

B*.log

Clogs/

D-i

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the destination directory.

Using options in wrong order.

The -v option shows what is moved, *.log selects all log files, and logs/ is the destination directory.

Practice

1. Which part of a Linux command tells the system what action to perform?

easy

A. The command

B. The options

C. The arguments

D. The file path

Solution

1. Step 1: Understand command structure basics

   A Linux command starts with the command itself, which tells the system what to do.

2. Step 2: Differentiate options and arguments

   Options modify the command's behavior, and arguments specify targets, but the command is the action.

3. Final Answer:

   The command -> Option A

4. Quick Check:

   Command = action [OK]

Hint: Command is always the first word in a Linux command line [OK]

Common Mistakes:

• Confusing options with commands
• Thinking arguments are commands
• Mixing file paths with commands

2. Which of the following is the correct syntax for using the ls command to list all files including hidden ones?

easy

A. ls -all

B. ls a-

C. ls -A

D. ls -a

Solution

1. Step 1: Identify correct option syntax

   Options usually start with a dash (-) followed by a letter or word. '-a' is the standard option for showing all files.

2. Step 2: Check common mistakes

   'a-' reverses the dash and letter, '-A' excludes . and .., '-all' is incorrect syntax.

3. Final Answer:

   ls -a -> Option D

4. Quick Check:

   Options start with dash + letter [OK]

Hint: Options start with dash (-) followed by letters [OK]

Common Mistakes:

• Reversing dash and option letter
• Using -A which excludes . and ..
• Using -all invalid syntax

3. What will be the output of the command echo -n Hello World?

medium

A. Hello World followed by a new line

B. -n Hello World

C. Hello World without a new line

D. Error: invalid option

Solution

1. Step 1: Understand the echo command and -n option

   The 'echo' command prints text. The '-n' option tells it not to add a new line at the end.

2. Step 2: Predict output behavior

   So, 'Hello World' will print exactly as is, without moving to a new line after.

3. Final Answer:

   Hello World without a new line -> Option C

4. Quick Check:

   echo -n = no newline [OK]

Hint: Remember: echo -n prints without newline [OK]

Common Mistakes:

• Assuming echo always adds newline
• Confusing -n as text
• Expecting error from -n option

4. Identify the error in the command: grep -i 'hello' file.txt -r

medium

A. The -r option is misplaced and invalid here

B. The quotes around 'hello' are incorrect

C. The file name should come before options

D. There is no error in this command

Solution

1. Step 1: Understand grep options and order

   '-i' is a valid option for case-insensitive search. '-r' is for recursive search but must come before arguments.

2. Step 2: Check option placement

   Options should come before arguments. Here, '-r' is after the file name, which is incorrect and causes error.

3. Final Answer:

   The -r option is misplaced and invalid here -> Option A

4. Quick Check:

   Options before arguments [OK]

Hint: Put all options before arguments in commands [OK]

Common Mistakes:

• Placing options after arguments
• Misusing quotes
• Assuming no error when order is wrong

5. You want to copy a file named report.txt to a directory /backup and preserve the file's timestamp. Which command is correct?

hard

A. cp report.txt /backup -p

B. cp -p report.txt /backup

C. cp /backup report.txt -p

D. cp report.txt -p /backup

Solution

1. Step 1: Recall cp command structure

   The command is 'cp', options come next, then source file, then destination directory.

2. Step 2: Identify correct option placement

   '-p' preserves timestamps and must come immediately after the command, before arguments.

3. Step 3: Validate each option

   cp report.txt /backup -p places '-p' after destination, which is incorrect. cp /backup report.txt -p reverses source and destination. cp report.txt -p /backup places '-p' between arguments, which is invalid.

4. Final Answer:

   cp -p report.txt /backup -> Option B

5. Quick Check:

   Command + options + source + destination [OK]

Hint: Options always come right after the command [OK]

Common Mistakes:

• Putting options after arguments
• Swapping source and destination
• Misplacing options between arguments