Johnson

To see the full log from systemctl status services, execute the “systemctl status service_name -l” command in the system.

To find the last login on Linux, use the “last”, “lastlog”, “/var/log/auth.log”, “who” and “lastb” commands that display username, terminal, date, and time.

Load average is the measure to determine the processes running or waiting to be run on the CPU. Three different methods can find the load average.

To find and change the MAC address, the ifconfig command, ip command, and “/sys/class/net/*/address” file are used in the system.

The Xmax scan can be performed using the nmap command in the system. This scan displays the status of the ports of the target machine.

The “/dev/null” is a powerful tool in Linux that allows users to discard unwanted data, suppress error messages, make files disappear, and many more.

Linux offers the “taskset” command to set or retrieve the CPU affinity of a running and a new process or thread in the operating system.

Linux offers the “sudo mkfs.xfs” command to create an XFS file system by specifying the partition name in the system.

Linux offers the “quotes”, “backslashes”, and “tab-completion” methods to read a filename with spaces in a specified directory.

To show the PATH of an environment variable, execute the “echo”, “cat”, “env”, “set”, and “printenv” commands with the “PATH” variable.

Linux offers the “sshpass -p [password] ssh [user]@[host]” command to connect to the remote host using a non-interactive SSH login.

The “utmp”, “wtmp”, and “btmp” files store the info of currently logged-in users, historical logs of all logins and logouts, and the failed login attempts.

Linux offers “mount”, “df”, “cat /proc/mounts”, “lsblk”, and “findmnt” commands to check the mounted filesystem along with the mount point.

The absolute path gives the exact location of a file or directory, while the relative path refers to the file and directory in the current working directory.

Linux offers the “mount” command to mount the file system or partition on a specific directory. It is useful to access and control the file system from the OS.

Linux offers the “nstat” command to display real-time network statistics in the terminal. Also, you can visualize the information about specific kernels.

Linux offers the “cat”, “less”, “more”, “head”, and “tail” commands to display the contents of a text file on the Linux command line.

Linux offers the “sestatus”, “getenforce” commands, and “etc/selinux/config” files to check whether SELinux is enabled or disabled.

Linux offers the “/etc/resolv.conf” file and the “Network Settings” in CLI and GUI methods to change the DNS server IP address in the system.

Linux offers the “smbpasswd” command with “-a” and “-x” options to add and delete samba users in Linux. For this, it is necessary to install the “samba” package.

Linux offers the “sysctl.conf” configuration file to permanently and temporarily disable the IPv6 services on Ubuntu 22.04 Jammy Jellyfish Linux.

Linux offers the built-in “OpenSSL” library to create the “.crt” file that establishes a secure connection between a server and a web browser.

Linux offers the “free”, “top”, “vmstat”, and “cat /proc/meminfo” commands and “System Monitor” application (GUI) to check the available memory.

Linux offers the “curl -A” option, the “.curlrc” file, and the “CURL_USER_AGENT” environment variable to set the user agent.

Linux offers the “nemo” command to install the Nemo file manager in the system. Also, you can configure it as a default and perform many actions.

Linux offers the “fallocate” command to create a swap file in the operating system by specifying the file name and desired size.

Linux offers the “hexdump” command to visualize the contents of a file in a hexadecimal and ASCII, canonical, and custom format string.

To kill a process in Linux, the “kill”, “kilall”, “pkill”, “xkill” and “top” commands are used.
They require the process name or id to kill the process.

To reload the changes to Systemd unit files, execute the “systemctl daemon-reload” command. Also, you can reload the specific unit files in the system.

To change the GRUB timeout in Linux, open the “/etc/default/grub” configuration file and set the “GRUB_TIMEOUT” value in seconds.

The boot loader loads the OS into memory and starts it. It is responsible for initializing the system, performing hardware tests, and giving control to the OS.

The “sshfs” command mounts the remote directory by specifying the local mount point. This command requires the “username” and “hostname” of the remote machine.

To unban an IP in fail2ban, the “fail2ban-client” utility is used by specifying the banned IP Address in IP List. This utility prevents unauthorized activity.

Linux offers the “cat” command to display the “MOTD” in the terminal. Also, users can display the custom MOTD after accessing the /etc/motd file.