Essential Tools

A system administrator needs to find all files in /var/log that have been modified in the last 2 hours. Which command should be used?

A user complains that the 'ls' command no longer outputs colors. The administrator suspects a change in environment variables. Which command would help diagnose the issue?

During a security audit, an administrator needs to list all TCP ports on which the system is listening, showing only the port numbers and the associated process names. Which command best achieves this?

A new Linux administrator needs to read the manual page for the 'ls' command but also wants to search for the word 'color' within the manual. Which command accomplishes this?

An administrator needs to terminate a hung process with PID 3456 that does not respond to 'kill -15 3456'. Which signal should be used next?

A backup script uses tar to create an archive, but the administrator wants to exclude the /tmp directory from the backup. Which tar option should be added?

An administrator wants to display a list of all currently logged-in users. Which command is most appropriate?

A developer needs to search for the string 'ERROR' in all files under /var/log, but wants to exclude files ending with '.gz'. Which command is correct?

Which TWO commands can be used to display the current date and time in a format like '2023-10-05 14:30:00'?

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

Which THREE commands can be used to check the disk space usage of the /home partition?

Refer to the exhibit. Why does the 'bin' user have /sbin/nologin as its shell?

Refer to the exhibit. Why does the /etc/shadow file have no read permissions for any user?

You are a system administrator for a company running Red Hat Enterprise Linux 8. A developer reports that a script which runs daily at 2 AM is failing. The script is located at /opt/scripts/backup.sh and is owned by root. The developer says the script runs fine when executed manually with './backup.sh' from the /opt/scripts directory. The script is scheduled via a root crontab entry: '0 2 * * * /opt/scripts/backup.sh'. However, the script fails because it cannot find a configuration file located at './config.ini'. What is the most likely cause and the correct solution?

You are a Linux administrator. A user reports that when they log in via SSH, they see the message 'Could not chdir to home directory /home/john: No such file or directory' and are dropped into the root directory. The user's home directory does exist at /home/john but is empty. The user's entry in /etc/passwd is: 'john:x:1001:1001::/home/john:/bin/bash'. What is the most likely cause and the correct fix?

A user reports that a script in their home directory fails to execute. The script has permissions -rw-r--r-- and is owned by the user. Which command will allow execution for the owner?

A system administrator needs to find all regular files larger than 10MB in /var/log. Which find command should they use?

An administrator wants to ensure that when a user presses Ctrl+C during a long-running script, the script cleans up temporary files before exiting. Which approach should the script use?

A user needs to view the last 15 lines of a log file that is constantly being updated. Which command should they use?

An administrator needs to compress a directory 'data' into an archive named backup.tar.gz using gzip compression. Which command should they use?

A system administrator needs to find all files modified in the last 24 hours under /var/log. Which command accomplishes this?

A user reports that they cannot use the 'systemctl' command to manage services. The user is part of the 'wheel' group. Which configuration change is required to allow this?

During boot, a server fails to mount an NFS filesystem listed in /etc/fstab. Which troubleshooting step should be taken first to isolate the issue?

An administrator wants to edit a configuration file and ensure only the intended changes are saved. Which practice is recommended?

A script needs to be run at system boot for a specific user. Which method ensures the script runs with that user's environment?

A server has a disk with LVM logical volumes. The administrator needs to extend a logical volume to use all remaining free space in the volume group. Which command sequence is correct?

Which command displays the current system time, timezone, and whether NTP synchronization is active?

An administrator needs to monitor network traffic on a specific interface in real time. Which tool is most appropriate for this task?

A developer needs to compile software from source and install it under /opt/custom. To avoid affecting the system package manager, which approach should be used?

Which TWO commands can be used to display the contents of a compressed log file without decompressing it first?

Which TWO methods can be used to permanently set the system's hostname to 'server01.example.com'?

Which THREE file descriptors are always available for every Unix process?

Which command displays the current working directory?

A user needs to find all files with the '.conf' extension under /etc. Which command should be used?

An administrator wants to gracefully terminate a process with PID 12345. Which command should be used?

A system administrator needs to replace all occurrences of 'enabled' with 'disabled' in /etc/ssh/sshd_config, but only on lines that do not start with '#'. Which sed command accomplishes this?

A user wants to display the contents of a file in reverse line order. Which command should be used?

An administrator needs to measure the execution time of the command 'backup.sh'. Which command prefix should be used?

A user is unable to delete a file named '-f' in the current directory. Which command will successfully remove it?

An administrator wants to create a symbolic link named 'link_to_hosts' in /tmp that points to /etc/hosts. Which command is correct?

An administrator needs to list the permissions, owner, group, and filenames of all files in /var/log, including hidden files, in a human-readable format. Which command does this?

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

Which THREE actions will create a new empty file named 'testfile' in the current directory? (Choose three.)

Which THREE commands can be used to monitor real-time process status and update the display every 2 seconds? (Choose three.)

Refer to the exhibit. What does the file permission -rw------- indicate about /etc/shadow?

Refer to the exhibit. Why did the sshd service fail?

Refer to the exhibit. The backup script runs every 5 minutes but generates errors. What is the most likely cause?

A system administrator needs to view the last 10 lines of the log file /var/log/messages in real time as new lines are added. Which command should be used?

A system administrator runs the command 'ls -l' and sees that a file has permissions '-rwxr-xr-x'. The administrator wants to remove execute permission for the group and others while keeping it for the owner. Which chmod command should be used?

A system administrator wants to find all files in /var that are larger than 100MB and have been modified within the last 7 days. The output should be a list of file paths with sizes in human-readable format, sorted by size descending. Which command pipeline accomplishes this?

A user wants to run a command in the background after logging out of an SSH session. Which method ensures the process continues even after logout?

An administrator receives an alert that a process named 'apache2' is consuming excessive CPU. The administrator needs to identify the PID of the process and then change its priority to the lowest possible value (least favorable scheduling). Which sequence of commands should be used?

A company policy requires that all cron jobs run by non-root users must be logged to a specific file /var/log/usercron.log. The system administrator decides to use rsyslog to capture these messages. Which configuration directive should be added to /etc/rsyslog.conf or a file in /etc/rsyslog.d/ to achieve this?

A user wants to set an environment variable named 'EDITOR' to the value '/usr/bin/vim' so that it is available in all future login sessions. Which file should the user add the export command to?

An administrator needs to compress a directory containing subdirectories and files into a single archive file, with maximum compression, and exclude all '*.tmp' files. Which command should be used?

A system administrator wants to monitor all files in /var/log that are currently being written to by processes. Which command shows file descriptors that are open for writing by any process?

Which TWO commands can be used to view the contents of a compressed file named 'data.log.gz' without decompressing it permanently? (Choose exactly two.)

Which THREE of the following are valid methods to schedule a recurring task in Red Hat Enterprise Linux 8? (Choose exactly three.)

Which TWO of the following are valid examples of using redirection and pipes in bash to append the output of a command to a file while also displaying it on the terminal? (Choose exactly two.)

Refer to the exhibit. An administrator runs these commands on a server. The administrator suspects a performance issue. Which observation from the exhibit is most likely causing a bottleneck?

A system administrator has created a new group named 'ops'. The administrator wants to add the existing user 'alice' to this group as a supplementary group without affecting her current group memberships. Which command should be used?

A system is experiencing high CPU usage. The administrator suspects a process is stuck in an infinite loop. Which command can be used to identify the most CPU-intensive process in real-time?

An administrator needs to schedule a script to run every Monday, Wednesday, and Friday at 2:30 PM. Which cron expression should be used?

A Red Hat Enterprise Linux server has been configured with a custom repository for offline updates. The administrator runs 'yum repolist' and the custom repository is not listed. Which command should be used to verify that the repository configuration file is valid and located in the correct directory?

Which two commands can be used to display the contents of a compressed .tar.gz archive without extracting it? (Choose two)

Which three of the following are valid methods to view the manual page for the 'ls' command? (Choose three)

A junior administrator is tasked with finding all files in the /var/log directory that have been modified within the last 24 hours and are owned by the 'root' user. The administrator runs the command: find /var/log -user root -mtime 0. However, the command returns no output, even though there are files that meet the criteria. What is the most likely issue with the find command?

A system administrator is trying to compress the contents of the directory /home/user/project into a tarball named project_backup.tar.gz using the command: tar -czf project_backup.tar.gz /home/user/project. The command completes without errors, but when the administrator tries to list the contents of the tarball using tar -tzf project_backup.tar.gz, it shows a leading slash (/) in the paths, like /home/user/project/file1. The administrator wants to create the tarball with relative paths instead. What change should be made to the tar command?

A Red Hat Enterprise Linux server has multiple network interfaces, and the administrator needs to ensure that the service 'httpd' starts automatically after a reboot. The administrator has already enabled the service using 'systemctl enable httpd', but after a reboot, the service is not running. The administrator checks the status and finds that the service is enabled but not started. The system uses systemd. Which additional step is required to ensure the service starts automatically at boot?

An administrator notices that the /tmp directory is filling up quickly. They want to find all files in /tmp that are larger than 100 MB and owned by user 'ftp', then delete them. The administrator runs: find /tmp -type f -size 100M -user ftp -exec rm {} \;. However, this command deletes only files that are exactly 100 MB, not larger. Which find expression should be used instead?

A system administrator is troubleshooting a cron job that runs a script as root. The script is located at /root/scripts/backup.sh and has permissions 755. The cron job is defined in /etc/crontab with the line: 0 2 * * * root /root/scripts/backup.sh. However, the script does not run at the scheduled time. The administrator checks the cron logs and finds no errors. The administrator then runs the script manually as root and it executes successfully. What is the most likely cause of the cron job not running?

Which TWO commands can be used to view the kernel ring buffer?

What does the 's' in the owner execute position indicate?

A system administrator notices that a server is responding slowly. The administrator runs `top` and sees a process named `backup_script` consuming 95% CPU. The process runs as root and is supposed to run nightly backups. However, the system load average is low. The administrator wants to investigate without killing the process. Which of the following is the best course of action?