An RSA key is a private key based on RSA algorithm, used for authentication and an symmetric key exchange during establishment of an SSL/TLS session.
The RSA private key in PEM format (the most common format for X.509 certificates, CSRs and cryptographic keys) can be generated from the command line using the openssl genpkey utility. (more…)
A minimal Docker image based on Alpine Linux has only 5 MB in size, but a lot of packages common for Linux distributions are not installed by default.
In this short note i will show how to install a package in Alpine container from the command line using the apk (Alpine package manager).
I will also show how to build an Alpine-based Docker image with additionally installed packages. (more…)
A Job in Jenkins can be scheduled for periodical builds in a declarative pipeline i.e. Jenkinsfile using a string in a cron-style syntax (with minor differences) defined in the triggers directive, for example triggers{cron('0 */3 * * *')}.
This note shows the examples of how to build Jenkins jobs and multi-branch pipelines periodically and how to schedule Jenkins jobs with parameters.
Also it shows the Jenkins cron syntax with examples. (more…)
The process identifier (a.k.a. process ID or PID) is a number used to uniquely identify an active process.
In this short note i will show how to display information about the Windows process (incl. the process name and path to an executable file) by PID from the command-line prompt (CMD) or a Windows PowerShell. (more…)
The touch command in Linux is used to change a file’s “Access“, “Modify” and “Change” timestamps to the current time and date, but if the file doesn’t exist, the touch command creates it.
If you simply want to create an empty file from the command-line prompt (CMD) or a Windows PowerShell – the type and copy commands can be considered as a Windows touch command equivalent.
The file timestamps in Windows can be changed using the built-in PowerShell commands. (more…)
Even though there is still no built-in Windows uptime command, the actual uptime of the server/workstation or the system boot time can be checked from the command-line.
In this note i will show several methods of how to check Windows uptime from the command-line prompt and PowerShell. (more…)
Git doesn’t allow to work on remote branches directly so you can’t literally checkout a remote branch.
If you want to checkout a remote branch, you need to create your own local “copy” of that branch and then check it out.
This note shows how to do this. (more…)
While using the screen command, you may notice that you can’t scroll up inside a screen session neither using the scroll bar or mouse wheel nor using the PageUp▲ or arrow up ↑ keys.
The scroll up seems to be not working because the screen command has its own scrollback buffer with the special key combinations for navigation.
In this short note i will show how to scroll up and navigate inside a screen session. (more…)
The Linux screen command is extremely useful for the cases when you need to start a long-running process on a remote machine.
Even if your connection drops and the SSH session is terminated, with the screen command you can be sure that the process will keep running in the background and the “lost” terminal session can be resumed.
This note shows how install and how to use the Linux screen command to run a process in the background. (more…)
Most Linux distributions use systemd as a system and service manager.
The systemctl is the main command in systemd, used to control services.
In this tutorial i will show how to list all, enabled and running systemd services using the systemctl command. (more…)