LPIC-1 Shells, Scripting and Data Management Practice Test 3 — 15 Questions

Question 1

A script produces both standard output and error messages. An administrator wants to save the output to 'out.log' and the error messages to 'err.log', but also wants to see both on the terminal. Which command achieves this?

Accepted Answer

./script.sh > >(tee out.log) 2> >(tee err.log). Option B is correct because it uses process substitution to tee each stream to both a file and the terminal. The 2>&1 in other options merges stderr into stdout, which is not desired.

Answer

./script.sh 2>&1 | tee out.log 2>&1 | tee err.log

Answer

./script.sh > out.log 2> err.log

Answer

./script.sh 2>&1 | tee out.log

Question 2

An administrator needs to replace all occurrences of 'old_host' with 'new_host' in the file /etc/hosts. Which sed command should be used?

Accepted Answer

sed -i 's/old_host/new_host/g' /etc/hosts. Option D is correct because sed -i edits the file in-place with global substitution. Without -i, changes are only displayed on stdout. Without the g flag, only the first occurrence per line is replaced.

Answer

sed -n 's/old_host/new_host/gp' /etc/hosts

Answer

sed -i 's/old_host/new_host/' /etc/hosts

Answer

sed 's/old_host/new_host/g' /etc/hosts

Question 3

A log file access.log contains multiple entries per IP address. An administrator wants to display a list of unique IP addresses sorted by frequency (most frequent first). Which command pipeline achieves this?

Accepted Answer

awk '{print $1}' access.log | sort | uniq -c | sort -rn. Option D is correct. First extract the IP field with awk, sort, then count duplicates with uniq -c, and finally sort numerically in reverse to show most frequent first.

Answer

awk '{print $1}' access.log | sort | uniq | sort -rn

Answer

awk '{print $1}' access.log | sort -rn | uniq -c

Answer

awk '{print $1}' access.log | sort | uniq -c | sort -k2

Question 4

A directory contains files with spaces and special characters in their names. An administrator wants to delete all files older than 30 days using find and xargs. Which command is safe?

Accepted Answer

find /path -type f -mtime +30 -print0 | xargs -0 rm. Option B is correct because -print0 and xargs -0 handle special characters by using null delimiters. Option A is unsafe due to word splitting. Options C and D do not use xargs.

Answer

find /path -type f -mtime +30 -delete

Answer

find /path -type f -mtime +30 -exec rm {} \;

Answer

find /path -type f -mtime +30 | xargs rm

Question 5

A user frequently runs 'ls -la' and wants to create an alias 'll' for this command. Which command adds this alias persistently?

Accepted Answer

alias ll='ls -la' && echo "alias ll='ls -la'" >> ~/.bashrc. Option C is correct because it both creates the alias in the current session and appends it to ~/.bashrc so it persists across sessions. Option A only creates a temporary alias. Option B adds to the file but does not activate it immediately. Option D exports a variable, not an alias.

Answer

export ll='ls -la'

Answer

echo "alias ll='ls -la'" >> ~/.bashrc

Answer

alias ll='ls -la'

Question 6

A script running as a daemon should perform clean-up operations when it receives SIGTERM. Which command inside the script sets up this behavior?

Accepted Answer

trap 'cleanup' SIGTERM. Option A is correct. trap with signal name SIGTERM (or number 15) runs the clean-up function when the signal is received. Options B and C use wrong syntax or signal. Option D uses EXIT, which runs on script exit from any cause.

Answer

trap cleanup TERM

Answer

trap 'cleanup' EXIT

Answer

trap "cleanup" 9

Question 7

A script starts multiple background processes. An administrator wants to wait for all background jobs to complete before proceeding. Which command should be used?

Accepted Answer

wait. Option C is correct. The wait command with no arguments waits for all background jobs to finish. Option A only waits for job 1. Option B sleeps a fixed time. Option D lists jobs but does not wait.

Answer

jobs -l

Answer

wait %1

Answer

sleep 5

Question 8

An administrator needs to find files that have been modified within the last 24 hours. Which two parameters are valid for the find command to accomplish this? (Choose TWO)

Accepted Answer

-mmin 1440. Option A is correct because `-mmin 1440` matches files whose data modification time is exactly 1440 minutes (24 hours) ago. Option B is correct because `-mtime 0` matches files modified within the last 24 hours (0 days ago). Both parameters target the modification time (`mtime`) and correctly interpret the time range as 'within the last 24 hours'.

Answer

-ctime 0

Answer

-newer file

Answer

-atime 1

Question 9

When writing a Bash script, which two constructs can be used to safely iterate over a list of filenames that may contain spaces or special characters? (Choose TWO)

Accepted Answer

find . -name '*.txt' -exec echo {} \;. Options C and D are correct. The while-read loop with NUL delimiter (C) safely handles any filename. The find -exec (D) processes each file separately without word splitting. Options A and E are unsafe due to word splitting. Option B expands to a single literal asterisk.

Answer

for file in *.txt; do ... done

Answer

for file in $(find . -name '*.txt'); do ... done

Answer

for file in "*.txt"; do ... done

Question 10

A sysadmin is tasked with configuring the shell environment for all users. Which three files are typically sourced by Bash during login? (Choose THREE)

Accepted Answer

~/.bash_profile. Option C is correct because during a login shell, Bash reads ~/.bash_profile (if it exists) to set user-specific environment variables and startup scripts. This file is sourced before ~/.profile and is the preferred file for login shell configurations, ensuring environment settings like PATH are applied.

Answer

~/.bashrc

Answer

/etc/bash.bashrc

Question 11

Refer to the exhibit. An administrator runs this command expecting to capture both stdout and stderr into output.txt. However, the file contains only stdout. What is the error?

Accepted Answer

The 2>&1 should appear after the > output.txt.. Option B is correct. In the command `command 2>&1 > output.txt`, the redirection order causes stderr to be redirected to the current stdout (terminal) before stdout is redirected to the file. Thus only stdout goes to the file, and stderr remains on the terminal. The correct order is `command > output.txt 2>&1`.

Answer

The file already exists and is not writable.

Answer

The stdout redirection should be 1> instead of >.

Answer

The command must be run as root.

Question 12

Refer to the exhibit. An application uses this JSON policy to control execution of commands. If a user tries to run /usr/bin/passwd, what will happen?

Accepted Answer

Denied because the deny rule is more specific.. Option B is correct. The policy defines an allow rule for /usr/bin/* and a specific deny rule for /usr/bin/passwd. Typically, deny rules override allow rules when both match, so the execution is denied.

Answer

Allowed because the allow rule matches.

Answer

The policy is invalid due to conflicting rules.

Answer

The path pattern does not match.

Question 13

Refer to the exhibit. An administrator wants to unset the BASH_ALIASES associative array. Which command will correctly remove it?

Accepted Answer

unset BASH_ALIASES. Option A is correct. The unset command without any options removes a variable or array. `unset BASH_ALIASES` will unset the variable. Options B and C are not valid syntax for unsetting. Option D is not a valid command.

Answer

export -n BASH_ALIASES

Answer

unset -v BASH_ALIASES

Answer

delete BASH_ALIASES

Question 14

A user needs to schedule a backup script to run every weekday at 2:00 AM. Which command should they use to set up this recurring job?

Accepted Answer

crontab -e and add a line. Option B is correct because crontab -e is used to edit the personal crontab file for recurring jobs. Option A is wrong because at is for one-time scheduling. Option C is wrong because sleep only delays execution. Option D is wrong because batch runs when the system load is low.

Answer

sleep 3600 && ./backup.sh

Answer

at -f backup.sh 2:00

Answer

batch

Question 15

A shell script uses the variable expansion ${var:-default} to set a default value for an environment variable. The script prints unexpected output when the variable is set to an empty string. Which expansion should be used to ensure the default is only used when the variable is unset, not when it is empty?

Accepted Answer

${var-default}. Option B is correct: ${var-default} expands to default only if var is unset, while ${var:-default} also expands to default if var is empty. Option A is wrong because it also handles empty. Option C assigns the default to the variable. Option D prints an error and exits.

Answer

${var:-default}

Answer

${var:?default}

Answer

${var:=default}