find by modification time in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Find files modified exactly 3 days ago

What is the output of this command if the directory contains files modified 1, 3, and 5 days ago?

find . -type f -mtime 3

Linux CLI

find . -type f -mtime 3

A Lists only files modified exactly 3 days ago

B Lists files modified more than 3 days ago

C Lists files modified within the last 3 days

D Lists files modified less than 3 days ago

💡 Hint

Remember, '-mtime n' matches files modified exactly n days ago.

The '-mtime 3' option finds files modified between 72 and 96 hours ago, not less or more.

💻 Command Output

intermediate

Find files modified less than 7 days ago

What does this command list?

find /tmp -type f -mtime -7

Linux CLI

find /tmp -type f -mtime -7

A Files modified between 7 and 14 days ago

B Files modified exactly 7 days ago

C Files modified more than 7 days ago

D Files modified less than 7 days ago

💡 Hint

The minus sign before 7 means less than 7 days.

The '-mtime -7' option matches files modified within the last 7 days (less than 7).

💻 Command Output

advanced

Find files modified more than 10 days ago

What output will this command produce?

find /var/log -type f -mtime +10

Linux CLI

find /var/log -type f -mtime +10

A Files modified less than 10 days ago

B Files modified exactly 10 days ago

C Files modified more than 10 days ago

D Files modified between 5 and 10 days ago

💡 Hint

The plus sign means strictly greater than the number of days.

The '-mtime +10' option finds files modified more than 10 days ago.

🔧 Debug

advanced

Why does this find command fail to list files modified in last 2 days?

You run:

find . -type f -mtime 2

but it does not list files modified yesterday. Why?

Linux CLI

find . -type f -mtime 2

A Because '-mtime 2' matches files modified exactly 2 days ago, not less

B Because '-mtime 2' matches files modified less than 2 days ago

C Because '-mtime 2' matches files modified more than 2 days ago

D Because '-mtime 2' matches files modified within last 2 days

💡 Hint

Check how '-mtime n' works with exact days.

The '-mtime 2' matches files modified between 48 and 72 hours ago, so files modified yesterday (less than 48 hours) are excluded.

🚀 Application

expert

Find and delete files older than 30 days safely

Which command safely finds and deletes files older than 30 days in /home/user/tmp?

A find /home/user/tmp -type f -mtime +30 | xargs rm

B find /home/user/tmp -type f -mtime +30 -delete

C find /home/user/tmp -type f -mtime +30 -exec rm -rf {} \;

D find /home/user/tmp -type f -mtime +30 -exec rm {} \;

💡 Hint

Use the safest and simplest way to delete files with find.

The '-delete' option deletes files safely and efficiently. Option B works but is slower. Option B uses '-rf' which is dangerous for files. Option B can fail with spaces in filenames.