LPIC-1 GNU and Unix Commands — Timed 10 Questions

Question 1

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?

10 minute time limit — choose an answer to begin.

Accepted Answer

sed -i 's/setting1=default/setting1=production/' /etc/example.conf; sed -i '/^include /a
setting2=value' /etc/example.conf. 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 2

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.. The issue is that with daily rotation, the delaycompress directive delays compression by only one rotation (one day). This means that rotated logs are compressed after one day, not after the desired 7 days. To meet the requirement that logs older than 7 days are compressed, the rotation frequency should be changed to weekly. With weekly rotation, delaycompress delays compression by one week, so logs younger than 7 days remain uncompressed and the most recent week's logs are available for troubleshooting.

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 3

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

Accepted Answer

1. Reboot the system. 2. Interrupt the GRUB bootloader. 3. Add 'init=/bin/bash' to the kernel command line. 4. Boot the system. 5. Remount the root filesystem as read-write. 6. Change the root password using passwd. 7. Reboot the system.. Recovery involves booting into a shell with root access, remounting read-write, and changing the password.

Answer

1. Reboot the system. 2. Interrupt the GRUB bootloader. 3. Add 'init=/bin/bash' to the kernel command line. 4. Boot the system. 5. Change the root password using passwd. 6. Remount the root filesystem as read-write. 7. Reboot the system.

Answer

1. Reboot the system. 2. Boot into single-user mode from GRUB. 3. Remount the root filesystem as read-write. 4. Change the root password using passwd. 5. Reboot the system.

Answer

1. Reboot the system. 2. Edit GRUB to add 'single' to the kernel line. 3. Boot the system. 4. Remount the root filesystem as read-write. 5. Change the root password using passwd. 6. Reboot the system.

Question 4

Match each device file naming pattern to its device type.

Accepted Answer

/dev/sda: SATA/SCSI hard disk. Common Linux device naming conventions: /dev/sdX for SATA/SCSI, /dev/hdX for IDE, /dev/ttySX for serial ports, /dev/srX for optical drives, /dev/nvmeXnY for NVMe. Be cautious not to confuse with floppy (/dev/fdX) or other types.

Answer

/dev/sr0: Floppy disk

Question 5

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' {} \;. 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 6

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. 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 7

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 user has no home directory. In an interactive shell, the HOME variable is typically exported by the login process and inherited by child processes. The most likely cause for $HOME being empty is that the user has no home directory defined in the password database (or the directory doesn't exist), which can cause the variable to be empty or unset in some configurations. Options A and B would not cause $HOME to be empty; using sh instead of bash or running with sudo would still provide a HOME value (possibly different) or set it to root's home.

Answer

The script is run with sh instead of bash

Answer

The script is run with sudo

Answer

The HOME variable is not exported

Question 8

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.. 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 9

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. 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 10

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