Backup strategies in Linux CLI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a compressed backup of the /home directory using tar.

Linux CLI

tar [1] -czf backup.tar.gz /home

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

A-c

B-x

C-v

D-r

Attempts:

3 left

💡 Hint

Common Mistakes

Using -x instead of -c will try to extract files instead of creating an archive.

Using -r appends files to an existing archive, not creating a new one.

The -c option tells tar to create a new archive.

2fill in blank

medium

Complete the command to synchronize the /data directory to /backup using rsync.

Linux CLI

rsync -a [1] /backup

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

A/backup

B/backup/

C/data

D/data/

Attempts:

3 left

💡 Hint

Common Mistakes

Using /data without trailing slash copies the directory itself inside /backup.

Confusing source and destination paths.

The source directory should be specified with a trailing slash to copy contents inside /data/.

3fill in blank

hard

Fix the error in the command to create an incremental backup with tar using the snapshot file.

Linux CLI

tar -czf backup.tar.gz --listed-incremental=[1] /var/log

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

Asnapshot-file

Bsnapshotfile

Csnapshot.file

Dsnapshot/file

Attempts:

3 left

💡 Hint

Common Mistakes

Using slashes in the snapshot file name causes path errors.

Using names without dots may be confusing but not wrong; however, the standard is to use a dot.

The snapshot file name should be a valid filename without special characters or slashes.

4fill in blank

hard

Fill both blanks to create a backup script that archives /etc and excludes *.tmp files.

Linux CLI

tar [1] -czf etc_backup.tar.gz /etc --exclude=[2]

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

A-c

B-x

C*.tmp

D*.log

Attempts:

3 left

💡 Hint

Common Mistakes

Using -x extracts files instead of creating an archive.

Excluding the wrong file pattern like *.log.

-c creates the archive, and --exclude=*.tmp skips temporary files.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps filenames to their sizes for files larger than 1MB.

Linux CLI

sizes = [1]: os.path.getsize([2]) for [3] in files if os.path.getsize([3]) > 1048576

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

Afilename

Bfile

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent variable names for keys and iteration.

Not filtering files by size correctly.

This comprehension creates a dictionary with filenames as keys and their sizes as values, filtering files larger than 1MB.

Practice

1. Which of the following best describes the main purpose of a backup in Linux?

easy

A. To delete old files to free up space

B. To install new software updates automatically

C. To speed up the computer by cleaning temporary files

D. To save copies of important files in a safe place

Solution

1. Step 1: Understand what a backup is

   A backup is a copy of important data saved separately to protect against loss.

2. Step 2: Match the description to the options

   Only To save copies of important files in a safe place describes saving copies in a safe place, which is the purpose of backups.

3. Final Answer:

   To save copies of important files in a safe place -> Option D

4. Quick Check:

   Backup = Save copies safely [OK]

Hint: Backups always mean saving copies, not deleting files [OK]

Common Mistakes:

• Confusing backup with deleting files
• Thinking backup speeds up the system
• Mixing backup with software updates

2. Which command syntax correctly copies a directory and its contents to a backup folder?

easy

A. cp -r /home/user/docs /backup/docs

B. cp /home/user/docs /backup/docs

C. cp -d /home/user/docs /backup/docs

D. cp -x /home/user/docs /backup/docs

Solution

1. Step 1: Identify the correct option to copy directories recursively

   The -r option in cp copies directories and their contents recursively.

2. Step 2: Check other options for correctness

   The plain cp lacks -r, so it won't copy directories properly. The options with -d and -x use invalid or unrelated flags.

3. Final Answer:

   cp -r /home/user/docs /backup/docs -> Option A

4. Quick Check:

   Copy directory = cp -r [OK]

Hint: Use cp -r to copy folders with all files inside [OK]

Common Mistakes:

• Forgetting the -r flag for directories
• Using wrong flags like -d or -x
• Assuming cp copies folders without options

3. What will be the output of this command if the source directory has files and the destination is empty?

rsync -av /home/user/data/ /backup/data/

medium

A. Only lists files without copying them

B. Copies all files and folders from /home/user/data to /backup/data preserving attributes

C. Deletes all files in /backup/data and leaves it empty

D. Shows an error because /backup/data does not exist

Solution

1. Step 1: Understand rsync options -a and -v

   The -a option means archive mode (copy recursively and preserve attributes), and -v means verbose (show progress).

2. Step 2: Analyze command behavior

   Since /backup/data exists and is empty, rsync copies all files and folders from source to destination preserving attributes.

3. Final Answer:

   Copies all files and folders from /home/user/data to /backup/data preserving attributes -> Option B

4. Quick Check:

   rsync -av copies files with details [OK]

Hint: rsync -av copies and shows details, no deletion by default [OK]

Common Mistakes:

• Thinking rsync deletes files by default
• Confusing verbose with dry-run
• Assuming error if destination exists

4. You wrote this script to backup a folder:

#!/bin/bash
cp -r /home/user/docs /backup/docs
rm -r /home/user/docs/*

What is the main problem with this backup strategy?

medium

A. It deletes original files after copying, risking data loss

B. It does not copy hidden files

C. It uses the wrong command to copy files

D. It will fail because /backup/docs does not exist

Solution

1. Step 1: Analyze the script commands

   The script copies /home/user/docs to /backup/docs, then deletes all files inside /home/user/docs.

2. Step 2: Identify risk in deleting original files

   Deleting original files after copying is risky if the copy failed or is incomplete, causing data loss.

3. Final Answer:

   It deletes original files after copying, risking data loss -> Option A

4. Quick Check:

   Deleting originals after backup = risk [OK]

Hint: Never delete originals immediately after backup without verification [OK]

Common Mistakes:

• Assuming cp misses hidden files (it copies them)
• Thinking /backup/docs must exist (cp creates it)
• Ignoring risk of deleting original data

5. You want to automate daily backups of /home/user/projects to /mnt/backup using tar. Which command correctly creates a compressed backup file with the current date in its name?

hard

A. tar -czf /home/user/projects /mnt/backup/projects-$(date +%F).tar.gz

B. tar -cf /mnt/backup/projects.tar.gz /home/user/projects

C. tar -czf /mnt/backup/projects-$(date +%F).tar.gz /home/user/projects

D. tar -xzf /mnt/backup/projects-$(date +%F).tar.gz /home/user/projects

Solution

1. Step 1: Understand tar options for creating compressed archives

   -c creates an archive, -z compresses with gzip, and -f specifies the output file.

2. Step 2: Check command correctness

   tar -czf /mnt/backup/projects-$(date +%F).tar.gz /home/user/projects correctly creates a gzip compressed archive named with the current date in /mnt/backup from /home/user/projects.

3. Final Answer:

   tar -czf /mnt/backup/projects-$(date +%F).tar.gz /home/user/projects -> Option C

4. Quick Check:

   tar -czf + date = compressed dated backup [OK]

Hint: Use tar -czf with $(date +%F) for dated compressed backups [OK]

Common Mistakes:

• Using -xzf which extracts instead of creates
• Swapping source and destination paths
• Omitting compression flag -z