LPIC-1 GNU and Unix Commands — 20 Questions

Question 1

A systems administrator needs to change the permissions of the file /home/user/script.sh so that the owner can read, write, and execute; the group can read and execute; and others have no access. Which command accomplishes this?

Accepted Answer

chmod 750 /home/user/script.sh. Option B is correct because chmod 750 sets the permissions to rwxr-x---, which gives the owner read, write, and execute (7), the group read and execute (5), and others no access (0). This matches the requirement exactly.

Answer

chmod 755 /home/user/script.sh

Answer

chmod 770 /home/user/script.sh

Answer

chmod 741 /home/user/script.sh

Question 2

Which TWO commands can be used to view the contents of a compressed file named archive.tar.gz without extracting it to disk?

Accepted Answer

tar -tzf archive.tar.gz. Option C is correct because the `tar -tzf` command lists the contents of a tar archive compressed with gzip without extracting it. The `-t` flag tells tar to list the table of contents, `-z` handles the gzip decompression on the fly, and `-f` specifies the archive file. This is the standard, single-command method for viewing the contents of a `.tar.gz` file without writing any files to disk.

Answer

gzip -d archive.tar.gz

Answer

bunzip2 -c archive.tar.gz | tar -t

Answer

gunzip -l archive.tar.gz

Question 3

Refer to the exhibit. An administrator needs to edit /etc/example.conf to change setting1 to 'production' and add a new line 'setting2=value' after the include line. The file must be edited in place without creating a backup. Which command sequence achieves this?

Accepted Answer

sed -i 's/setting1=default/setting1=production/' /etc/example.conf; sed -i '/^include /a
setting2=value' /etc/example.conf. Option A is correct because the first sed command uses the -i flag to edit the file in place without a backup, and the substitution 's/setting1=default/setting1=production/' changes the existing setting. The second sed command uses the 'a' (append) command after the line matching '^include ' to add the new line 'setting2=value' after it, also with -i to avoid creating a backup.

Answer

sed -i 's/setting1=default/setting1=production/' /etc/example.conf; sed -i '/^include /i
setting2=value' /etc/example.conf

Answer

sed -i.bak 's/setting1=default/setting1=production/' /etc/example.conf; sed -i.bak '/^include /a
setting2=value' /etc/example.conf

Answer

sed -i.bak 's/setting1=default/setting1=production/' /etc/example.conf; sed -i.bak '/^include /a
setting2=value' /etc/example.conf

Question 4

You are a Linux administrator for a company that runs a web server on a system with limited disk space. The web server logs are stored in /var/log/httpd/access_log and grow quickly. The operations team requires that the most recent logs be available for troubleshooting, but logs older than 7 days must be compressed to save space. You decide to implement log rotation using logrotate. The logrotate configuration file for httpd currently contains:

/var/log/httpd/*.log {
    daily
    rotate 7
    compress
    delaycompress
    missingok
    notifempty
    sharedscripts
    postrotate
        /bin/systemctl reload httpd 2>/dev/null || true
    endscript
}

After applying this configuration, you notice that log files are being compressed immediately instead of after one rotation. What is the most likely cause and the correct step to fix this?

Accepted Answer

Change the rotation frequency to 'weekly' so that the most recent week's logs remain uncompressed and older logs are compressed.. Option B is correct because the configuration uses 'rotate 7' with 'daily' frequency, meaning seven daily rotations are kept. However, 'delaycompress' delays compression by one rotation, so the most recent rotated log remains uncompressed. With 'daily' rotation, the current log and the most recent rotated log are both uncompressed, which may appear as if compression happens immediately. Changing to 'weekly' ensures that only the most recent week's logs remain uncompressed, matching the requirement that logs older than 7 days are compressed.

Answer

Remove the 'sharedscripts' directive to ensure the postrotate script runs for each log file individually.

Answer

Remove the 'delaycompress' directive to ensure compression occurs at each rotation.

Answer

Add the 'copytruncate' directive to avoid moving the log file, allowing the web server to continue writing to the same file.

Question 5

Arrange the steps to configure a static IP address on a Linux system using the command line.

Question 6

Order the steps to recover a forgotten root password on a Linux system.

Question 7

Match each Linux runlevel to its typical description.

Question 8

Match each device file naming pattern to its device type.

Question 9

A systems administrator needs to find all files in /var/log that were modified in the last 24 hours and contain the word 'error'. Which command accomplishes this?

Accepted Answer

find /var/log -mtime 0 -exec grep -l 'error' {} \;. Option B is correct because it uses `find` with `-mtime 0` to locate files modified within the last 24 hours, then pipes each found file to `grep -l` to print only filenames containing 'error'. The `-exec` option runs `grep` on each file individually, and `-l` ensures only matching filenames are output, not the matching lines.

Answer

grep -r 'error' /var/log -mtime 0

Answer

find /var/log -mmin 1440 -exec grep 'error' {}

Answer

ls -l /var/log | grep error

Question 10

An administrator wants to change the ownership of a file to user 'jane' and group 'staff'. Which command should be used?

Accepted Answer

chown jane:staff file. Option C is correct because the `chown` command with the syntax `chown user:group file` changes both the user and group ownership of a file in a single command. This is the standard POSIX syntax, where a colon separates the user and group names, allowing the administrator to set ownership to user 'jane' and group 'staff' atomically.

Answer

chown jane.staff file

Answer

chgrp jane staff file

Answer

chown jane staff file

Question 11

A developer is troubleshooting a shell script that uses the variable $HOME but it outputs nothing when the script runs. The script is executed with ./script.sh from an interactive shell. What is the most likely cause?

Accepted Answer

The HOME variable is not exported. Option C is correct because the HOME variable is typically set by the login process and exported to the environment. If the script is run in a context where HOME is not exported (e.g., a non-interactive shell or a script that clears the environment), the variable will be empty. The script uses $HOME, which expands to nothing if HOME is unset or not exported, causing the output to be empty.

Answer

The script is run with sh instead of bash

Answer

The script is run with sudo

Answer

The user has no home directory

Question 12

An administrator needs to copy a directory hierarchy from one server to another over SSH, preserving permissions, ownership, and timestamps. Which command is most appropriate?

Accepted Answer

tar cf - /source | ssh user@dest "tar xf - -C /target". Option B is correct because it uses `tar` to create an archive of the source directory, pipes it over SSH, and extracts it on the remote server with `tar xf - -C /target`. This method preserves all file metadata (permissions, ownership, timestamps) because `tar` captures and restores these attributes by default, and the pipe over SSH transfers the raw archive without any transformation. Unlike `scp` or `rsync` (without root privileges), this approach can preserve ownership even when the user is not root, as long as the remote `tar` runs with appropriate privileges.

Answer

cp -a /source /mnt/remote

Answer

scp -rp /source user@dest:/target

Answer

rsync -avz /source user@dest:/target

Question 13

An administrator runs the command 'find / -name "*.conf" 2>/dev/null | head -n 10' and notices that the command returns very quickly. Which statement best describes what happened?

Accepted Answer

It scans the entire filesystem but stops after sending the first 10 lines to head due to a broken pipe.. Option A is correct because the `find` command starts scanning the entire filesystem from root (`/`), but its output is piped to `head -n 10`, which reads only the first 10 lines and then closes the pipe. When `head` closes the pipe, `find` receives a SIGPIPE signal (broken pipe) and terminates early, so the command returns very quickly without scanning the entire filesystem.

Answer

It lists 10 .conf files only from the current directory because the path is /.

Answer

It lists all .conf files in the filesystem because head only affects output, not find.

Answer

It lists only the first 10 .conf files found in the filesystem.

Question 14

A script uses 'set -e' and then executes 'grep pattern file'. If the pattern is not found, the script exits. Which of the following modifications would prevent the script from exiting while still allowing detection of the pattern's absence?

Accepted Answer

set +e; grep pattern file; exit_code=$?; set -e. Option B is correct because it temporarily disables 'set -e' with 'set +e', runs the grep command, captures its exit code in a variable, then re-enables 'set -e'. This allows the script to continue executing after a non-zero exit from grep, while still preserving the exit code for later conditional checks. The other options either fail to preserve the exit code or do not prevent the script from exiting under 'set -e'.

Answer

grep -q pattern file || true

Answer

grep pattern file; exit_code=$?

Answer

grep pattern file | head -1

Question 15

Refer to the exhibit. Which file has a special permission that allows a user to execute the file with the privileges of the file owner?

Accepted Answer

/usr/bin/su. The /usr/bin/su command has the SUID (Set User ID) special permission set (typically mode 4755). This allows any user who executes the file to run it with the effective user ID of the file owner (root), enabling privilege escalation to perform administrative tasks. The SUID bit is represented by an 's' in the owner's execute position when viewed with ls -l.

Answer

/usr/bin/myapp

Answer

/tmp/shared

Answer

None of the above

Question 16

Refer to the exhibit. The process with PID 1234 is in state 'Z'. What is the most likely cause and appropriate action?

Accepted Answer

The process is a zombie; the parent process must be killed or wait for it to be reaped.. In Linux process states, 'Z' indicates a zombie process, which is a child process that has terminated but whose exit status has not yet been read by its parent process via the wait() system call. The correct action is to either kill the parent process (so that the zombie is reaped by init) or ensure the parent calls wait() to reap the child. Option D correctly identifies this.

Answer

The process is stopped; use kill -CONT to continue.

Answer

The process is a daemon; it should be restarted.

Answer

The process is sleeping; wait for it to become ready.

Question 17

Refer to the exhibit. Which file system is full and what is the likely consequence if the administrator does not take action?

Accepted Answer

/dev/sdb1 is full; applications writing to /var may fail.. The exhibit shows that /dev/sdb1, mounted on /var, has 0% available space (100% used). The /var directory stores variable data such as logs, spool files, and temporary files. If /var fills up, critical services like syslog, cron, or package managers (e.g., apt, yum) cannot write to their log or spool files, causing applications that depend on /var to fail. This is why option D is correct.

Answer

Both are full; system will crash.

Answer

/dev/sda1 is full; system may become unstable.

Answer

Neither is full; available space is sufficient.

Question 18

Which TWO commands can be used to display the contents of a compressed file without decompressing it to disk? (Choose two.)

Accepted Answer

zcat file.gz. A is correct because `zcat` reads a gzip-compressed file and writes its decompressed content to standard output without saving the decompressed data to disk. This allows you to view the contents of `file.gz` directly in the terminal or pipe it to other commands.

Answer

gzip -d file.gz

Answer

tar -xzf file.tar.gz

Answer

uncompress file.Z

Question 19

Which TWO of the following are valid methods to run a shell script named 'script.sh' using the bash shell, assuming the script has execute permission? (Choose two.)

Accepted Answer

./script.sh. Option A is correct because './script.sh' explicitly invokes the script using the current shell's shebang interpreter (e.g., #!/bin/bash) and requires execute permission. Option E is correct because 'bash script.sh' runs the script as an argument to the bash interpreter, which reads and executes the file line by line, also requiring execute permission.

Answer

sh script.sh

Answer

script.sh (if in PATH)

Answer

source script.sh

Question 20

Which THREE of the following are correct features of the 'grep' command? (Choose three.)

Accepted Answer

-i makes the search case-insensitive. Option A is correct because the `-i` flag in `grep` performs case-insensitive matching, so patterns like 'error' will match 'Error', 'ERROR', etc. This is a common requirement when searching log files where case may vary.

Answer

-l prints line numbers of matches

Answer

-r enables regular expression matching