find by name, type, and size in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Find files named 'report.txt' of type regular file

What is the output of this command if the current directory contains exactly one regular file named 'report.txt' and no other files with that name?

find . -name 'report.txt' -type f

Linux CLI

find . -name 'report.txt' -type f

A ./report.txt

B

./report.txt/
./report.txt

C report.txt

D No output

💡 Hint

The command finds regular files named exactly 'report.txt' in the current directory and subdirectories.

The find command prints the relative path starting with './' for files found. Since there is one regular file named 'report.txt' in the current directory, it outputs './report.txt'.

💻 Command Output

intermediate

Find directories named 'backup' larger than 1MB

What will this command output if there is one directory named 'backup' with size 2MB and one file named 'backup' with size 3MB?

find . -name 'backup' -type d -size +1M

Linux CLI

find . -name 'backup' -type d -size +1M

A ./backup/file.txt

B

./backup
./backup/file.txt

C No output

D ./backup

💡 Hint

The command looks for directories named 'backup' larger than 1MB, not files.

The command finds directories (-type d) named 'backup' with size greater than 1MB. Only the directory matches, so it outputs './backup'.

📝 Syntax

advanced

Correct find command to locate regular files named '*.log' smaller than 500KB

Which option is the correct find command to locate regular files with names ending in '.log' and size less than 500KB?

A find . -name '*.log' -type f -size -500k

B find . -name '*.log' -type f -size +500k

C find . -type f -name '*.log' -size -500k

D find . -name '*.log' -type d -size -500k

💡 Hint

Order of options does not matter, but size sign and type must be correct.

Option C correctly finds regular files (-type f) named '*.log' with size less than 500KB (-size -500k). Option C uses lowercase 'k' which is valid but order is less conventional. Option C uses +500k which means larger than 500KB. Option C searches directories (-type d) which is incorrect.

🔧 Debug

advanced

Why does this find command fail to find files larger than 1MB?

Given this command:

find /data -type f -name '*.csv' -size +1M

It returns no results even though there are CSV files larger than 1MB. What is the most likely reason?

Linux CLI

find /data -type f -name '*.csv' -size +1M

A The size option counts 512-byte blocks, so '+1M' means files larger than 1*512 bytes

B The '+1M' means files larger than 1MB, so it should be '-1M' to find larger files

C The size unit 'M' is case sensitive and should be lowercase 'm'

D The command is correct; the files are probably smaller than 1MB

💡 Hint

Check how the find command interprets size units by default.

By default, find's '-size' option counts in 512-byte blocks unless a unit is specified. 'M' means mebibytes (1,048,576 bytes). If the system does not support 'M' or the version is old, it may interpret '+1M' as '+1 * 512 bytes' which is very small. This causes unexpected results.

🚀 Application

expert

Find all empty directories named 'temp' and delete them safely

Which command will find all empty directories named 'temp' under /var/log and delete them safely, prompting before each deletion?

A find /var/log -type d -name 'temp' -empty -delete

B find /var/log -type d -name 'temp' -empty -exec rm -ri {} +

C find /var/log -type d -name 'temp' -empty -exec rm -r {} \;

D find /var/log -type d -name 'temp' -empty -exec rm -i {} \;

💡 Hint

You want to delete directories safely with confirmation and only empty ones named 'temp'.

Option B uses '-empty' to find empty directories named 'temp' and '-exec rm -ri {} +' to remove them interactively, prompting before each deletion. Option B deletes without prompt. Option B deletes recursively without prompt. Option B deletes interactively but not recursively, which fails for directories.

Practice

1. What does the find command option -name do in Linux CLI?

easy

A. Searches files or directories by their name pattern

B. Filters files by their size

C. Lists all files in the current directory

D. Changes the name of a file

Solution

1. Step 1: Understand the -name option

   The -name option in the find command is used to search for files or directories that match a specific name pattern.

2. Step 2: Compare with other options

   Options like filtering by size or listing files are done with other flags, not -name.

3. Final Answer:

   Searches files or directories by their name pattern -> Option A

4. Quick Check:

   -name = Search by name [OK]

Hint: Remember: -name matches file names exactly [OK]

Common Mistakes:

• Confusing -name with size filters
• Thinking -name lists files
• Using -name to rename files

2. Which of the following is the correct syntax to find all regular files named report.txt in the current directory and its subdirectories?

easy

A. find . -type f -name report.txt

B. find . -name "report.txt" -type d

C. find . -type f -name "report.txt"

D. find / -type f -name report.txt

Solution

1. Step 1: Understand the syntax for find

   The correct syntax requires the path (here . for current directory), the type -type f for regular files, and the name pattern with quotes -name "report.txt" to match the exact file name.

2. Step 2: Check each option

   find . -type f -name report.txt misses quotes around the name, which can cause issues with special characters. find . -name "report.txt" -type d searches for directories (-type d) not files. find / -type f -name report.txt searches from root /, not current directory. find . -type f -name "report.txt" is correct with quotes and correct type.

3. Final Answer:

   find . -type f -name "report.txt" -> Option C

4. Quick Check:

   Quotes + correct type + current dir = find . -type f -name "report.txt" [OK]

Hint: Always quote the name pattern to avoid shell issues [OK]

Common Mistakes:

• Omitting quotes around the name
• Using wrong type flag (-type d instead of -type f)
• Searching from wrong directory

3. What will be the output of the command find /tmp -type f -size +1M -name "*.log" assuming there are two files: /tmp/app.log (500K) and /tmp/error.log (2M)?

medium

A. /tmp/app.log
/tmp/error.log

B. /tmp/error.log

C. /tmp/app.log

D. " (no output)

Solution

1. Step 1: Understand the command filters

   The command searches in /tmp for regular files (-type f) with size greater than 1 megabyte (-size +1M) and names ending with .log (-name "*.log").

2. Step 2: Apply filters to given files

   /tmp/app.log is 500K, which is less than 1M, so excluded. /tmp/error.log is 2M, which matches size and name filters, so included.

3. Final Answer:

   /tmp/error.log -> Option B

4. Quick Check:

   Size +1M and name *.log = /tmp/error.log [OK]

Hint: Size +1M means files larger than 1 megabyte [OK]

Common Mistakes:

• Including files smaller than 1M
• Ignoring the name pattern
• Confusing +1M with exactly 1M

4. You run the command find . -type f -name *.txt -size -10k but get an error or unexpected results. What is the likely problem?

medium

A. The command needs sudo to run

B. Wrong size flag; should be +10k instead of -10k

C. Using -type f instead of -type d

D. Missing quotes around *.txt causing shell expansion

Solution

1. Step 1: Identify the issue with -name pattern

   The pattern *.txt without quotes is expanded by the shell before find runs, causing unexpected behavior or errors.

2. Step 2: Correct usage with quotes

   Enclosing *.txt in quotes like "*.txt" prevents shell expansion and lets find correctly match file names.

3. Final Answer:

   Missing quotes around *.txt causing shell expansion -> Option D

4. Quick Check:

   Always quote patterns in -name [OK]

Hint: Quote wildcards in -name to avoid shell expansion [OK]

Common Mistakes:

• Not quoting the name pattern
• Confusing size flags + and -
• Using wrong type flag

5. You want to find all directories named backup larger than 100MB inside /var. Which command correctly achieves this?

hard

A. find /var -type d -name "backup" -size +100M -exec du -sh {} \;

B. find /var -type d -name "backup" -size +100M

C. find /var -type d -name "backup" -exec du -sh {} \; | awk '$1 > 100M'

D. find /var -type d -name "backup" -size +100M -size +100M

Solution

1. Step 1: Understand find limitations on directory size

   The -size option measures file size, but for directories it measures disk usage metadata, not total content size.

2. Step 2: Use -exec du -sh to get actual directory size

   find /var -type d -name "backup" -size +100M -exec du -sh {} \; uses -exec du -sh {} to show human-readable size of each directory found, which helps verify size over 100MB.

3. Step 3: Confirm correct filtering

   find /var -type d -name "backup" -size +100M incorrectly uses -size +100M on directories which is unreliable. find /var -type d -name "backup" -exec du -sh {} \; | awk '$1 > 100M' tries to filter with awk but size format is not numeric only. find /var -type d -name "backup" -size +100M -size +100M repeats -size +100M unnecessarily.

4. Final Answer:

   find /var -type d -name "backup" -size +100M -exec du -sh {} \; -> Option A

5. Quick Check:

   Use -exec du -sh to check directory sizes [OK]

Hint: Use du with -exec to measure directory size [OK]

Common Mistakes:

• Relying on -size for directory content size
• Not quoting the name pattern
• Repeating size filters unnecessarily