This tutorial shows you step-by-step how to add a user to a group on Linux, with several examples using the Linux command line. It also explains how to add users and groups on Linux. The commands should work on any Linux distribution and have been tested on CentOS, Debian, and Ubuntu. Add a new Linux ... Read more
Even though a file is held by root and has 700 rights, if the root user saves it in another user's home directory or any other directory owned by another user, that user can remove the file. Example: root@workstation:/home/otheruser# ls -la total 8 drwxr-xr-x 2 otheruser otheruser 4096 Jul 28 11:52 . drwxr-xr-x 3 root ... Read more
The shell setting in /etc/passwd determines whether a Linux system user may log in via the shell or over SSH. If you don't want a certain user to be able to log in, set the shell to /bin/false or /sbin/nologin. For the user "otheruser" on Debian and Ubuntu Linux, here's an example: usermod -s /bin/false ... Read more
If you have a directory with many files (a few thousand in my case) and need to know which one is the newest, then the following command might be useful. It returns the name and details of the newest file in a directory where it is executed: ls -tl | sed -n 2p
Sometimes you might want to download an entire website e.g. to archive it or read it offline. This tutorial will show you which application can be used on Windows and Linux. I will use the tool wget here, which's a command-line program that is available for Windows, Linux, and MAC. Install wget on Windows First, download and ... Read more
JPEG is a lossy compression file format for digital images. It can greatly reduce the amount of storage space used by a graphics file compared to the PNG format. This tutorial describes how to convert a PNG file to JPG on the shell. I use the GraphicsMagick command-line tool on my Ubuntu 20.04 system to ... Read more
The bash history is a log file that contains all commands that the user executed on the Linux shell. When you use the "arrow up" key on our keyboard, then Bash will look up the previous command from that file and display it on the screen, ready to be executed again. Bash history file location The ... Read more
The Linux TigerVNC Server provides a command to set a new password. Set VNC Password The command is "vncpasswd", the password is stored in encrypted form into the file ~/.vnc/passwd of the home directory of the user. Run: vncpasswd to set a new password for the currently logged-in user. The command will then prompt for the ... Read more
There is no simple 'tolower' command on the bash, but you can convert uppercase characters to lowercase with a little shell script. The script uses the tr command internally for converting the chars. Create a shell script with the name 'tolower' that converts all text that is given as a command-line argument to lower case: ... Read more
Here is a short script that helped me to copy files that have ben modified within the last 60 minutes to a new directory. The script uses a combination of the find and cp commands, it has to be run inside the directory that contains the new files. In this example, I will copy all ... Read more