ls options (-l, -a, -h, -R) in Linux CLI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the -l option do in the ls command?

The -l option shows a detailed list of files and directories. It includes permissions, number of links, owner, group, size, and modification date.

beginner

What is the purpose of the -a option in ls?

The -a option shows all files, including hidden files that start with a dot (.), which are normally not shown.

beginner

Explain what the -h option does when used with ls -l.

The -h option makes file sizes easier to read by showing them in human-friendly units like KB, MB, or GB instead of bytes.

intermediate

What does the -R option do in the ls command?

The -R option lists directories and their contents recursively, showing all files and folders inside subdirectories.

intermediate

How would you combine ls options to see all files with detailed info and human-readable sizes?

Use ls -lah. This shows all files including hidden ones (-a), detailed info (-l), and human-readable sizes (-h).

Which ls option shows hidden files?

A -l

B -h

C -a

D -R

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

What does ls -lh display?

A List files with permissions only

B List only hidden files

C List files recursively

D List files with detailed info and human-readable sizes

-l shows detailed info and -h makes sizes human-readable.

Which option lists directory contents recursively?

A -R

B -h

C -l

D -a

The -R option lists all directories and subdirectories recursively.

What information does ls -l NOT show?

A File content

B File size

C File owner

D File permissions

ls -l shows metadata but not the actual content of files.

How do you show all files including hidden ones with detailed info?

A ls -a

B ls -la

C ls -l

D ls -h

ls -la combines -l for details and -a for hidden files.

Describe what each of these ls options does: -l, -a, -h, and -R.

Think about what you want to see: details, hidden files, easy sizes, or all folders inside folders.

How would you use ls options to list all files including hidden ones, with sizes easy to read, and detailed info?

Combine the options that show details, hidden files, and human-friendly sizes.

Practice

1. What does the ls -a command do in Linux?

easy

A. Shows all files including hidden ones

B. Lists files with detailed information

C. Displays file sizes in human-readable format

D. Lists files recursively in subdirectories

Solution

1. Step 1: Understand the -a option

   The -a option in ls shows all files, including hidden files that start with a dot.

2. Step 2: Compare with other options

   Other options like -l show details, -h shows sizes human-readable, and -R lists recursively.

3. Final Answer:

   Shows all files including hidden ones -> Option A

4. Quick Check:

   -a means show hidden files [OK]

Hint: Remember: 'a' for all files including hidden [OK]

Common Mistakes:

• Confusing -a with -l for detailed info
• Thinking -a shows sizes in human format
• Assuming -a lists files recursively

2. Which of the following is the correct syntax to list files with detailed info and human-readable sizes?

easy

A. ls -la

B. ls -lR

C. ls -h -a

D. ls -lh

Solution

1. Step 1: Combine options for detailed and human-readable

   The -l option shows detailed info, and -h makes sizes human-readable. Together, ls -lh is correct.

2. Step 2: Check option order and other choices

   A (ls -la) shows detailed info including hidden files but misses human-readable sizes. C (ls -h -a) misses detailed info. D (ls -lR) lists recursively, not human-readable sizes.

3. Final Answer:

   ls -lh -> Option D

4. Quick Check:

   -l + -h = detailed + human sizes [OK]

Hint: Use -l and -h together for details and friendly sizes [OK]

Common Mistakes:

• Mixing up option order and meaning
• Using -h without -l for details
• Confusing -R with -h

3. What will be the output of ls -lR in a directory with two subfolders, each containing files?

medium

A. Lists files in current directory only

B. Shows file sizes in human-readable format

C. Lists files with details in current and all subdirectories

D. Lists hidden files only

Solution

1. Step 1: Understand -lR options

   -l lists files with details, and -R lists recursively through all subdirectories.

2. Step 2: Predict output behavior

   The command will show detailed info for files in the current directory and all files in subfolders recursively.

3. Final Answer:

   Lists files with details in current and all subdirectories -> Option C

4. Quick Check:

   -lR = detailed + recursive listing [OK]

Hint: Remember -R means recursive, -l means detailed [OK]

Common Mistakes:

• Thinking -R lists hidden files only
• Assuming -lR shows human-readable sizes
• Believing it lists only current directory

4. You ran ls hR but got an error: "ls: cannot access 'hR': No such file or directory". What is the likely cause?

medium

A. Options must be combined without spaces

B. You typed options together without a dash

C. Options order is incorrect

D. You used uppercase letters instead of lowercase

Solution

1. Step 1: Analyze the error message

   The error "ls: cannot access 'hR': No such file or directory" suggests the shell interpreted 'hR' as a file or directory name.

2. Step 2: Identify correct option syntax

   Options must be preceded by a dash and can be combined like -hR. Typing ls hR without dash causes the shell to treat 'hR' as a filename.

3. Final Answer:

   You typed options together without a dash -> Option B

4. Quick Check:

   Options need dash prefix [OK]

Hint: Always prefix options with a dash (-) [OK]

Common Mistakes:

• Using uppercase instead of lowercase options
• Putting spaces between dash and options
• Assuming option order matters

5. You want to list all files including hidden ones, with detailed info and human-readable sizes, recursively through all subdirectories. Which command should you use?

hard

A. ls -alhR

B. ls -lha

C. ls -aRl

D. ls -l -a -h

Solution

1. Step 1: Identify needed options

   You need -a for hidden files, -l for detailed info, -h for human-readable sizes, and -R for recursive listing.

2. Step 2: Combine options correctly

   All options can be combined as -alhR. ls -alhR: ls -alhR includes all needed options.

3. Step 3: Check other options

   B (ls -lha) misses recursive -R. C (ls -aRl) includes all options but order does not matter in Linux, so it is also correct. D (ls -l -a -h) misses recursive -R.

4. Final Answer:

   ls -alhR -> Option A

5. Quick Check:

   All needed options combined = ls -alhR [OK]

Hint: Combine all needed options with one dash for full listing [OK]

Common Mistakes:

• Forgetting -R for recursion
• Not combining options properly
• Using options without dash