Backup automation script in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a backup directory if it does not exist.

Bash Scripting

if [ ! -d [1] ]; then
  mkdir -p /backup
fi

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

A/tmp

B/home

C/backup

D/var

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong directory path.

Forgetting the exclamation mark to negate the condition.

The script checks if the /backup directory exists. If not, it creates it using mkdir -p.

2fill in blank

medium

Complete the code to copy all files from /data to the backup directory.

Bash Scripting

cp -r /data/* [1]

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

A/backup

B/tmp

C/var

D/home

Attempts:

3 left

💡 Hint

Common Mistakes

Copying to the wrong directory.

Forgetting the -r flag for directories.

The cp command copies all files and folders from /data to /backup recursively.

3fill in blank

hard

Fix the error in the code to archive the backup directory into a tar.gz file.

Bash Scripting

tar -czf [1] /backup

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

Abackup.tar

Bbackup.gz

Cbackup.zip

Dbackup.tar.gz

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong file extension like .zip or .gz alone.

Omitting the -z flag for compression.

The tar command with -czf creates a compressed tar.gz archive. The file should end with .tar.gz.

4fill in blank

hard

Fill both blanks to check if the backup archive exists and print a success message.

Bash Scripting

if [ -f [1] ]; then
  echo [2]
fi

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

Abackup.tar.gz

B"Backup completed successfully!"

C"Backup failed!"

Dbackup.zip

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for wrong file name.

Printing failure message on success check.

The script checks if the backup.tar.gz file exists and prints a success message if true.

5fill in blank

hard

Fill all three blanks to create a timestamped backup filename and archive the backup directory.

Bash Scripting

timestamp=$(date +[1])
backup_file=[2]_$timestamp.tar.gz
tar -czf [3] /backup

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

A"%Y%m%d_%H%M%S"

Bbackup

C$backup_file

Dbackup.tar.gz

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong date format string.

Not using the variable for the archive filename.

Hardcoding the archive filename instead of using timestamp.

The date command formats the timestamp, backup_file uses it in the name, and tar archives using that filename.

Practice

1. What is the main purpose of a backup automation script in bash?

easy

A. To delete old files from the system

B. To automatically copy important files to a safe location regularly

C. To speed up the computer by closing programs

D. To change file permissions for security

Solution

1. Step 1: Understand the goal of backup automation

   A backup automation script is designed to save copies of important files automatically to prevent data loss.

2. Step 2: Identify the correct purpose among options

   Only To automatically copy important files to a safe location regularly describes copying files regularly to a safe place, which matches backup automation.

3. Final Answer:

   To automatically copy important files to a safe location regularly -> Option B

4. Quick Check:

   Backup automation = automatic file copying [OK]

Hint: Backup scripts copy files automatically to protect data [OK]

Common Mistakes:

• Confusing backup with deleting files
• Thinking backup speeds up the system
• Mixing backup with changing permissions

2. Which of the following bash commands correctly creates a backup directory with today's date?

easy

A. mkdir backup-$(date +%Y-%m-%d)

B. mkdir backup_date

C. mkdir backup $(date +%d-%m-%Y)

D. mkdir backup-`date +%Y/%m/%d`

Solution

1. Step 1: Understand date command format for folder naming

   The format +%Y-%m-%d gives a date like 2024-06-15, which is safe for folder names.

2. Step 2: Check each mkdir command for correctness

   mkdir backup-`date +%Y/%m/%d` uses backticks (valid) but produces slashes (/), invalid for folder names. mkdir backup_date uses a literal string without date. mkdir backup $(date +%d-%m-%Y) has a space causing two arguments to mkdir ('backup' and date string). mkdir backup-$(date +%Y-%m-%d) uses correct $( ) substitution and safe hyphen-separated format.

3. Final Answer:

   mkdir backup-$(date +%Y-%m-%d) -> Option A

4. Quick Check:

   Safe date format with mkdir = mkdir backup-$(date +%Y-%m-%d) [OK]

Hint: Use $(date +%Y-%m-%d) for safe folder names [OK]

Common Mistakes:

• Using slashes in folder names
• Not using command substitution syntax
• Using underscores instead of date command

3. What will be the output of this script snippet?

backup_dir="backup-$(date +%Y-%m-%d)"
mkdir -p "$backup_dir"
cp -r /home/user/documents "$backup_dir"

Assuming today's date is 2024-06-15 and the documents folder exists.

medium

A. Throws an error because of missing quotes

B. Creates a folder named backup-$(date +%Y-%m-%d) and copies documents inside it

C. Creates a folder named backup-2024-06-15 and copies documents inside it

D. Copies documents to the current directory without creating a folder

Solution

1. Step 1: Evaluate variable assignment and command substitution

   The variable backup_dir will be set to backup-2024-06-15 because $(date +%Y-%m-%d) runs and inserts the date.

2. Step 2: Understand mkdir and cp commands with quotes

   mkdir -p creates the directory if it doesn't exist. cp -r copies the documents folder recursively into the backup directory. Quotes ensure spaces are handled safely.

3. Final Answer:

   Creates a folder named backup-2024-06-15 and copies documents inside it -> Option C

4. Quick Check:

   Command substitution + mkdir + cp = Creates a folder named backup-2024-06-15 and copies documents inside it [OK]

Hint: Quotes and $(date) create dated backup folders safely [OK]

Common Mistakes:

• Not using quotes causing errors with spaces
• Misunderstanding command substitution syntax
• Assuming cp copies files without -r for folders

4. Identify the error in this backup script snippet:

backup_dir=backup-$(date +%Y-%m-%d)
mkdir $backup_dir
cp -r /home/user/docs $backup_dir

medium

A. Missing quotes around $backup_dir may cause errors if folder name has spaces

B. mkdir command should be mkdir -r instead of mkdir

C. cp command should not use -r for copying directories

D. Date format in variable assignment is incorrect

Solution

1. Step 1: Check mkdir command usage

   mkdir without -p is okay if folder doesn't exist, but missing quotes around $backup_dir can cause issues if the folder name contains spaces.

2. Step 2: Check cp command and date format

   cp -r is correct for copying directories. Date format is valid. The main issue is missing quotes around variable usage.

3. Final Answer:

   Missing quotes around $backup_dir may cause errors if folder name has spaces -> Option A

4. Quick Check:

   Always quote variables with spaces in paths [OK]

Hint: Always quote variables when used as paths [OK]

Common Mistakes:

• Using mkdir -r which is invalid
• Not using -r with cp for directories
• Incorrect date format syntax

5. You want to automate backups of the /var/log directory daily, keeping backups for 7 days only. Which script snippet correctly creates a dated backup folder and deletes backups older than 7 days?

hard

A. backup_dir="backup-$(date +%Y-%m-%d)"
mkdir -p "$backup_dir"
cp -r /var/log "$backup_dir"
find . -name 'backup-*' -delete

B. backup_dir=backup-$(date +%Y-%m-%d)
mkdir $backup_dir
cp /var/log $backup_dir
rm -rf backup-*

C. backup_dir="backup-$(date +%Y-%m-%d)"
mkdir -p "$backup_dir"
cp -r /var/log "$backup_dir"
rm -rf backup-*

D. backup_dir="backup-$(date +%Y-%m-%d)"
mkdir -p "$backup_dir"
cp -r /var/log "$backup_dir"
find . -maxdepth 1 -name 'backup-*' -mtime +7 -exec rm -rf {} +

Solution

1. Step 1: Create dated backup folder and copy logs

   Snippets using backup_dir="backup-$(date +%Y-%m-%d)" (double quotes), mkdir -p "$backup_dir", cp -r /var/log "$backup_dir" correctly create dated folder and copy recursively. The other lacks quotes, -p, -r so may fail.

2. Step 2: Remove backups older than 7 days safely

   rm -rf backup-* and find . -name 'backup-*' -delete delete all backups without age check. Only find . -maxdepth 1 -name 'backup-*' -mtime +7 -exec rm -rf {} + limits to top-level, selects >7 days old, deletes safely.

3. Final Answer:

   backup_dir="backup-$(date +%Y-%m-%d)" mkdir -p "$backup_dir" cp -r /var/log "$backup_dir" find . -maxdepth 1 -name 'backup-*' -mtime +7 -exec rm -rf {} + -> Option D

4. Quick Check:

   Safe find with -maxdepth and -mtime +7 = backup_dir="backup-$(date +%Y-%m-%d)" mkdir -p "$backup_dir" cp -r /var/log "$backup_dir" find . -maxdepth 1 -name 'backup-*' -mtime +7 -exec rm -rf {} + [OK]

Hint: Use find with -mtime +7 and -maxdepth 1 to delete old backups [OK]

Common Mistakes:

• Deleting all backups instead of only old ones
• Missing -p in mkdir causing errors
• Using cp without -r for directories
• Not limiting find depth risking unwanted deletions