010-160 The Power OF The Command Line Practice Test 5 — 15 Questions

Question 1

A junior administrator runs `grep -r "timeout" /etc` inside a Bash login shell. The output scrolls past the terminal window, so the administrator wants to view the complete results one screen at a time while also being able to scroll back through the earlier lines. Which command should the administrator have used instead?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

grep -r "timeout" /etc | less. Sending the recursive grep results through a pager is the standard way to review long output interactively. The less pager presents one screenful at a time and supports scrolling backward and forward, so the administrator can read every matched line and revisit earlier ones. The other choices either discard the output, duplicate the original scrolling behaviour, or detach the job without improving readability.

Answer

grep -r "timeout" /etc &

Answer

grep -r "timeout" /etc | tee

Answer

grep -r "timeout" /etc > /dev/null

Question 2

While troubleshooting a script, you run `grep -n 'error' /var/log/app.log` and see output lines prefixed with numbers. A colleague asks what those numbers represent. What do they indicate?

Accepted Answer

The line number in the file where each matching line occurs.. The -n flag tells grep to prefix each matching line with its line number in the source file. This helps pinpoint where matches occur without opening an editor. Other grep flags like -c count matches and -b show byte offsets, but only -n provides the line position shown in the scenario.

Answer

The total count of matching lines found in the file.

Answer

The process ID of the application that wrote each log entry.

Answer

The byte offset from the start of the file to each match.

Question 3

A new administrator wants to see the manual page for the `cp` command to check its options. Which command should they run?

Accepted Answer

man cp. The man command is the standard interface to the system's manual pages. Running `man cp` displays the cp manual, covering syntax, options, and examples. Other tools like help are limited to shell built-ins, and info or custom doc commands are not universally available or standard for this purpose.

Answer

info cp

Answer

doc cp

Answer

help cp

Question 4

While troubleshooting a service, a technician runs `ps aux` and sees a process in state `Z`. The process's parent is PID 1. Which statement best describes what the technician is observing?

Accepted Answer

The process has terminated, but its exit status has not yet been read by its parent.. A process in state Z is a zombie: it has already terminated, but its parent has not yet collected its exit status. The kernel retains a small entry until the parent calls wait(). Since the parent is PID 1, which normally reaps promptly, a lingering zombie points to a reaping problem rather than a running or stopped process.

Answer

The process is sleeping and is waiting for a signal to wake it.

Answer

The process is running in the foreground and has high CPU priority.

Answer

The process is stopped by a job control signal and can be resumed with `fg`.

Question 5

A user wants to find all files under /var/log that have been modified within the last 24 hours and are larger than 1 MB, then save the list to /tmp/recent_large.txt. Which command accomplishes this?

Accepted Answer

find /var/log -type f -mtime -1 -size +1M > /tmp/recent_large.txt. The find command is designed to search for files based on metadata such as modification time and size. Using -mtime -1 selects files modified within the last 24 hours, and -size +1M selects files larger than 1 MB. Redirection saves the output. The other commands lack these filtering capabilities or misinterpret the options.

Answer

ls -lR /var/log | awk '$6 > 1 && $7 > 1' > /tmp/recent_large.txt

Answer

locate -mtime -1 -size +1M /var/log > /tmp/recent_large.txt

Answer

grep -R -l --include='*' -mtime -1 -size +1M /var/log > /tmp/recent_large.txt

Question 6

A user is at the shell prompt and wants to display the current working directory. Which command should be used?

Accepted Answer

pwd. The pwd command prints the absolute pathname of the current working directory. Other commands like cd change directories, ls lists contents, and dir is not the standard tool for this purpose. pwd is a fundamental command for orientation in the filesystem.

Answer

dir

Answer

ls

Answer

cd

Question 7

A user needs to find every regular file under /var/log whose name ends in `.log` and whose size is larger than 10 megabytes, then delete them. Which command accomplishes this safely?

Accepted Answer

find /var/log -type f -name '*.log' -size +10M -delete. The find command with -type f, -name '*.log', -size +10M, and -delete precisely targets regular files larger than 10 MB with the .log suffix and removes them. It avoids content-based matching, does not rely on parsing ls output, and does not risk recursive directory deletion, making it the safe and correct choice.

Answer

ls -l /var/log/*.log | awk '$5>10485760 {print $9}' | rm

Answer

find /var/log -name '*.log' -size +10M -exec rm -rf {} \;

Answer

grep -rl '*.log' /var/log | xargs rm -f

Question 8

A user wants to count the number of lines in a file named 'access.log'. Which command should be used?

Accepted Answer

wc -l access.log. The wc -l command is specifically designed to count lines in a file by counting newline characters. It is efficient, simple, and the de facto standard for this task. The other commands either display the file, use a less direct method, or introduce unnecessary complexity and potential inaccuracies.

Answer

head -n 999999 access.log | wc -l

Answer

cat -n access.log

Answer

grep -c '' access.log

Question 9

You need to determine the absolute path of the `python3` executable that would run if you typed `python3` at the prompt. Which command displays this path?

Accepted Answer

which python3. The which command resolves a command name using the PATH variable and prints the first executable found. whereis, locate, and find do not determine execution order based on PATH.

Answer

whereis python3

Answer

find / -name python3

Answer

locate python3

Question 10

A user wants to find all files under /home that are larger than 100 MB and were modified in the last 7 days. Which command accomplishes this?

Accepted Answer

find /home -type f -size +100M -mtime -7. The correct command uses -type f for regular files, -size +100M for files larger than 100 MB, and -mtime -7 for files modified within the last 7 days. The other options either match exact sizes, exact ages, or use +7 which selects older files, failing the scenario's criteria.

Answer

find /home -type f -size 100M -mtime 7

Answer

find /home -type f -size +100M -mtime +7

Answer

find /home -name '*' -size +100M -mtime +7

Question 11

A user wants to run a command that will continue running even after the terminal is closed. Which command should be used to achieve this?

Accepted Answer

nohup ./long_script.sh &. To keep a process running after the terminal closes, use nohup to ignore hangup signals and & to run it in the background. This detaches the process from the terminal's session. The other commands either do not start a new process, require a different syntax, or do not prevent termination on terminal close.

Answer

screen ./long_script.sh

Answer

bg ./long_script.sh

Answer

disown ./long_script.sh

Question 12

A user wants to redirect the standard error of a command to a file named errors.txt while still displaying standard output on the terminal. Which redirection is correct?

Accepted Answer

command 2> errors.txt. To redirect only standard error, use 2> filename. This leaves standard output untouched on the terminal. The > operator redirects only standard output, 2>&1 > file redirects error to the terminal and output to file, and &> redirects both streams to the file.

Answer

command &> errors.txt

Answer

command 2>&1 > errors.txt

Answer

command > errors.txt

Question 13

A script named deploy.sh must run only when the preceding build command finishes without error. Which shell operator should you place between the two commands to achieve this?

Accepted Answer

&&. Exit statuses drive shell control flow: zero means success, non-zero means failure. The && operator performs a logical AND on those statuses, executing its right operand only after a successful left operand. Chaining the build command with deploy.sh through && therefore guarantees deployment happens solely on a clean build, which is the standard idiom in shell scripts.

Answer

||

Answer

|

Answer

;

Question 14

Which TWO of the following commands can be used to view the contents of a file named 'data.txt'? (Choose two.)

Accepted Answer

cat data.txt. The cat and less commands both display the contents of a file. cat outputs the entire file at once, while less provides a paginated view. The other commands either search for patterns, count statistics, or print a literal string, none of which show the file's contents.

Answer

wc data.txt

Answer

grep data.txt

Answer

echo data.txt

Question 15

A user runs `grep -E '^[A-Z][a-z]+ [0-9]{3}$' file.txt` and gets no output, even though file.txt contains lines like `Alpha 123` and `Beta 456`. What is the most likely explanation?

Accepted Answer

The pattern requires exactly one uppercase letter followed by one or more lowercase letters, then a space, then exactly three digits, and the end of line; the lines may contain trailing spaces or other characters.. The regex anchors to the full line with ^ and $. If the lines contain trailing whitespace, carriage returns, or other invisible characters, the pattern will not match despite the visible text appearing correct. This is the most common cause of such a failure when the regex itself is syntactically valid.

Answer

The pattern requires the first letter to be uppercase and the rest lowercase, but the lines start with uppercase and have digits, which is not allowed by [a-z]+.

Answer

The pattern uses {3} which is not supported by grep without the -P option.

Answer

The -E option is invalid for grep and causes it to ignore the pattern.