find with -exec for actions in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of find with -exec to list files

What is the output of this command if the current directory contains files file1.txt and file2.log only?

find . -name '*.txt' -exec ls -l {} \;

Linux CLI

find . -name '*.txt' -exec ls -l {} \;

A No output, command fails

B Lists detailed info of file2.log only

C Lists detailed info of file1.txt only

D Lists detailed info of both file1.txt and file2.log

💡 Hint

The command finds files ending with .txt and runs ls -l on each.

The find command searches for files matching '*.txt' and runs 'ls -l' on each found file. Only file1.txt matches, so only its details are listed.

💻 Command Output

intermediate

Effect of find with -exec rm on files

Given a directory with files a.txt, b.txt, and c.log, what files remain after running?

find . -name '*.txt' -exec rm {} \;

Linux CLI

find . -name '*.txt' -exec rm {} \;

A Only c.log remains

B All files remain

C Only a.txt remains

D Only b.txt remains

💡 Hint

The command deletes files ending with .txt.

The find command locates all files ending with .txt and deletes them with rm. Only c.log remains.

📝 Syntax

advanced

Correct syntax for find with -exec to move files

Which option correctly moves all .log files to /backup using find with -exec?

A find . -name '*.log' -exec mv {} /backup \;

B find . -name '*.log' -exec mv {} /backup ;

C find . -name '*.log' -exec mv {} /backup \

D find . -name '*.log' -exec mv {} /backup

💡 Hint

The -exec command must end with an escaped semicolon.

The correct syntax requires the escaped semicolon '\;' to mark the end of the command for -exec. Options B, C, and D miss this or have wrong escaping.

🔧 Debug

advanced

Why does this find with -exec command fail?

This command is intended to compress all .txt files with gzip:

find . -name '*.txt' -exec gzip {} ;

Why does it fail?

Linux CLI

find . -name '*.txt' -exec gzip {} ;

A The find command needs -print before -exec

B gzip command does not accept file arguments

C The wildcard '*.txt' is not quoted

D Missing escape before semicolon causes syntax error

💡 Hint

Check how the semicolon is written at the end of -exec.

The semicolon must be escaped as '\;' to prevent shell interpreting it. Without escape, find sees syntax error.

🚀 Application

expert

Count files modified in last 7 days and delete them

Which command correctly finds files modified in the last 7 days and deletes them safely using find with -exec?

A find . -type f -mtime 7 -exec rm {} \;

B find . -type f -mtime -7 -exec rm -i {} \;

C find . -type f -mtime +7 -exec rm -f {} \;

D find . -mtime -7 -exec rm {}

💡 Hint

Use -mtime with negative value for files modified within last N days and confirm deletion.

Option B finds files modified less than 7 days ago and deletes them interactively (-i). Others either use wrong time, no confirmation, or missing escape.

Practice

1. What does the -exec option do in the find command?

easy

A. Changes the permissions of files found automatically.

B. Runs a specified command on each file found by find.

C. Lists only directories found by find.

D. Deletes all files found without confirmation.

Solution

1. Step 1: Understand the purpose of -exec

   The -exec option in find runs a command on each file found by the search.

2. Step 2: Differentiate from other options

   It does not delete, list only directories, or change permissions by itself; it just runs the given command.

3. Final Answer:

   Runs a specified command on each file found by find. -> Option B

4. Quick Check:

   -exec runs commands on found files [OK]

Hint: Remember: -exec means "execute command" on files [OK]

Common Mistakes:

• Thinking -exec deletes files automatically
• Confusing -exec with listing or filtering options
• Forgetting to end -exec command with \;

2. Which of the following is the correct syntax to delete all .log files using find with -exec?

easy

A. find . -name '*.log' -exec rm {}

B. find . -name '*.log' -exec rm {} ;

C. find . -name '*.log' -exec rm {} \;

D. find . -name '*.log' -exec rm \;

Solution

1. Step 1: Identify correct -exec ending

   The -exec command must end with \; to mark the end of the command.

2. Step 2: Check command correctness

   find . -name '*.log' -exec rm {} \; correctly uses rm {} and ends with \;. Other options miss the backslash or semicolon or both.

3. Final Answer:

   find . -name '*.log' -exec rm {} \; -> Option C

4. Quick Check:

   Correct -exec ends with \; [OK]

Hint: Always end -exec commands with \; [OK]

Common Mistakes:

• Omitting the backslash before semicolon
• Leaving out the semicolon entirely
• Not using {} as placeholder for file name

3. What will be the output of this command?

find /tmp -type f -name '*.txt' -exec echo File: {} \;

medium

A. Deletes all .txt files in /tmp directory.

B. Shows an error because echo cannot be used with -exec.

C. Lists only the names of .txt files without path.

D. Prints 'File: ' followed by each .txt file path found in /tmp.

Solution

1. Step 1: Understand the command

   The command finds all files ending with .txt in /tmp and runs echo File: {} on each.

2. Step 2: Predict output

   For each file found, it prints "File: " followed by the full file path (because {} is replaced by the path).

3. Final Answer:

   Prints 'File: ' followed by each .txt file path found in /tmp. -> Option D

4. Quick Check:

   -exec echo File: {} prints file paths [OK]

Hint: Remember {} is replaced by each file path found [OK]

Common Mistakes:

• Thinking it deletes files
• Assuming only file names print without path
• Believing echo can't be used with -exec

4. Identify the error in this command:

find /var/log -name '*.log' -exec gzip {} ;

medium

A. Missing backslash before semicolon in -exec ending.

B. Incorrect use of quotes around '*.log'.

C. Using gzip instead of gunzip.

D. No error; command is correct.

Solution

1. Step 1: Check -exec syntax

   The -exec command must end with \;, not just ;.

2. Step 2: Validate other parts

   Quotes around '*.log' are correct, and gzip is appropriate to compress logs.

3. Final Answer:

   Missing backslash before semicolon in -exec ending. -> Option A

4. Quick Check:

   -exec must end with \; [OK]

Hint: Check for \ before ; to end -exec [OK]

Common Mistakes:

• Using ; without backslash
• Confusing compression commands
• Removing quotes around patterns

5. You want to find all files larger than 5MB in /home/user and change their permissions to 644. Which command correctly uses find with -exec to do this?

hard

A. find /home/user -size +5M -exec chmod 644 {} \;

B. find /home/user -size +5M -exec chmod 644 {} ;

C. find /home/user -size +5M -exec chmod 644 \;

D. find /home/user -size +5M -exec chmod 644 {}

Solution

1. Step 1: Understand size filter and command

   -size +5M finds files larger than 5MB. chmod 644 {} changes permissions of each found file.

2. Step 2: Confirm correct -exec syntax

   The command must end with \; to mark the end of the -exec action. find /home/user -size +5M -exec chmod 644 {} \; correctly includes this.

3. Final Answer:

   find /home/user -size +5M -exec chmod 644 {} \; -> Option A

4. Quick Check:

   Use -exec with {} and end with \; [OK]

Hint: Use {} for file and end -exec with \; [OK]

Common Mistakes:

• Omitting {} placeholder
• Missing backslash before semicolon
• Leaving out semicolon entirely