Quick Answer
The answer is `lsof /path/to/file`. This command is the correct choice because `lsof` stands for "list open files," and it queries the kernel to report every process that currently has a given file descriptor open. When you specify a file path, `lsof` returns the process ID (PID) and the process name holding that file, directly revealing which process is using the file. On the CompTIA Linux+ XK0-005 exam, this question tests your ability to troubleshoot file-locking issues and resource contention, often appearing in scenarios where a file cannot be unmounted or deleted. A common trap is confusing `lsof` with `fuser`—while both can identify file users, `lsof` provides more detailed output including the file descriptor type and access mode. For a memory tip, think "List Open Files" to recall `lsof`, and remember that without a path, it dumps every open file on the system, so always specify the file to narrow results.
This XK0-005 practice question tests your understanding of troubleshooting. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A system administrator needs to find out which process is using a particular file. Which command should they use?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
fuser /path/to/file
Why wrong: fuser also shows PIDs, but lsof is more widely used and provides more detail.
lsof /path/to/file
lsof lists all open files and the processes that opened them.
ps aux | grep file
Why wrong: ps shows running processes, not which files they have open.
stat /path/to/file
Why wrong: stat shows file metadata, not which process has it open.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
lsof /path/to/file
The `lsof` command (list open files) is the correct tool because it displays information about files opened by processes, including the specific file path. When given a file path, `lsof` lists the PID and process name that currently have that file open, directly answering the administrator's need.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
fuser /path/to/file
Why it's wrong here
fuser also shows PIDs, but lsof is more widely used and provides more detail.
lsof /path/to/file
Why this is correct
lsof lists all open files and the processes that opened them.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
ps aux | grep file
Why it's wrong here
ps shows running processes, not which files they have open.
stat /path/to/file
Why it's wrong here
stat shows file metadata, not which process has it open.
Common exam traps
The trap here is that candidates may confuse `fuser` with `lsof` because both can identify processes using a file, but `lsof` provides more comprehensive output and is the standard tool for detailed process-to-file mapping in the XK0-005 exam.
Trap categories for this question
Command / output trap
fuser also shows PIDs, but lsof is more widely used and provides more detail.
Detailed technical explanation
Under the hood, `lsof` reads kernel data structures such as the file descriptor table for each process, which is stored in `/proc/<PID>/fd/` on Linux. This allows it to list all open file handles, including regular files, directories, sockets, and pipes. In a real-world scenario, if a file cannot be unmounted because it is in use, `lsof` can pinpoint the exact process (e.g., a background daemon or a user's shell) holding the file open, enabling targeted troubleshooting.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Troubleshooting — study guide chapter
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FAQ
Troubleshooting — This question tests Troubleshooting — Read the scenario before looking for a memorised answer..
The correct answer is: lsof /path/to/file — The `lsof` command (list open files) is the correct tool because it displays information about files opened by processes, including the specific file path. When given a file path, `lsof` lists the PID and process name that currently have that file open, directly answering the administrator's need.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
This XK0-005 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the XK0-005 exam.
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