In Ubuntu, the “clean”, “autoclean”, and “autoremove” commands clean up the system cache, additional dependencies, and outdated versions of packages.

To add new lines, use the “-e(backspace interpreter)” and “$(bash variable)” with the “echo” command. An “echo” tool can also be used multiple times to do this.

In Linux and its distributions, the “curl” can be installed via default package managers i.e “apt” (Ubuntu/Debian), “yum” (CentOS/RHEL), and “dnf” (Fedora).

To generate a strong password, use the “urandom”, “makepasswd”, “gpg”, “apg”, “pwgen”, and “openssl rand” commands. It can also be done using the “Perl” script.

The “cd -” and “cd ~-” jump into the recently used directory but the “cd -” also prints that directory’s absolute path in the terminal.

To copy a directory and its content to the new location, use the “cp” with the “R” flag, “rsync,” and ”tar” commands, or a GUI method.

Use the “for” and “while” loops in the shell script to read the file content line by line. Both these loops provide simple syntax to perform this task easily.

The error is caused when the user tries to change the hostname, which is not found in the /etc/hosts file, and it is fixed by adding the hostname to that file.

Different errors can be made while editing a text file using nano; use the “ALT+U” key to undo the operations and “CTRL+E” to redo the changes made.

In Linux, the error “cp: omitting directory” represents that the “cp” command expects a file as the source, not a directory.

In Linux, to check the hard disk performance of the system, the user can consider the utilities such as “hdparm”, “dd ”, “iostat”, or the “Disks” tool.

In Linux, To find the process ID of the process using the specific port, use the “netstat”, “ss”, “losf”, or the “fuser” utility.

To check the RAM size in the Linux, utilize the “/proc/meminfo file”, “free”, “top”, “vmstat”, “dmidecode”, “lshw”, or “hwinfo” utilities

Linux offers the “systemctl” and “service” commands to restart the “SSH” service instantly. It can also be restarted by accessing the “/etc/init.d” directory.

In Linux, use the default package managers of Linux distribution, i.e., “apt(Ubuntu/Debian)” and “dnf(Fedora/CentOS/RHEL)” to completely remove the Virtualbox.

To change an IP address, utilize the “ip”, “ifconfig”, and the “nmcli” command line tools or the “Network” window in the GUI method.

In Linux, the “for” loop executes the block of statements repeatedly for every item in a list. It offers two types of syntax, i.e., “generalized” and “one line”.

To find and kill the zombie process on Linux, list down the zombie process, and send the SIGCHLD signal to its parent process.

The find -mtime +1 only returns files older than two days because it only returns the files modified in the last two or less than two days.

To export a GPG private and public key, use the “gpg –export-secret-key -a > prv.key” and “gpg –export -a > pub.key” commands.

To add a DNS server via resolv.conf configuration file, add a nameserver directive followed by the IP address of the DNS server.

To step into, step over, and step out with GDB, use the “step”, “next”, and “finish” commands. These GDB commands quickly identify and fix bugs in the program.

To install and run the TFTP server, execute the “sudo apt install tftpd-hpa” command and configure the “tftpd-hpa” configuration file.

Linux and its distributions offer the pre-installed “id”, “echo”, “lslogin”, and “getent” command line utilities for finding user ID from the terminal.

To give full permission to a folder and its subfolders, use the “chmod 777 ” command and hit the “Properties” option by specifying the folder.

To reduce the file size of the scanned PDF, use the command line utilities ghostscript (gs), and “ps2pdf” or utilize the PDF online compression tool.

The binary files in Linux are analyzed through the file, ldd, hexdump, strings, readelf, objdump, strace, ltrace, and xxd utilities.

To force a clock update using the NTP server, use the “ntpdate” command and “ntpd” service. They synchronize the time on the system with the time NTP server.

To find out which users are in a group within Linux, utilize the “groups”, “getent”, and “id -Gn” commands and the “/etc/group” file.

To reverse SSH tunneling connection, execute the “ssh -R :localhost: @” command.

The difference between cp -r and cp -a is that cp -a preserves all file attributes, while cp -r only preserves the ownership and permissions of the files.

Discover if there’s a free VPN service compatible with Ubuntu. Learn about the best options and benefits of using a VPN on Ubuntu.

The “onworks” platform offers to run various operating systems on the browser. Read this post to check how it works for Linux.

The “remove”, “autoremove”, and “purge” functionalities of Linux OSs allow the user to get rid of the executables, dependencies, and configurations of Apache.