Understanding file permissions and ownership on Linux

The files on a Linux system can have reading permissions, writing permissions, executing (running) permissions or no permissions for the user that owns that files, groups of users or the rest – users who does not own that files and they are not members of any group.

Extract audio from video file

Since there are so many tools (Minitube, youtube-dl) which allows you to download video files from YouTube or other video sharing sites, let’s go one step further and extract the sound from the downloaded video file to a mp3 file. The FFmpeg tool will do the trick just fine

CLI search and replace in multiple files

Here is a quick tip about how to find and replace a text in multiple files, from CLI.In this example you have some text files (.txt) with urls like “http://example.com, http://another-example.com…”. What you are trying to do is to replace all “http” references with “https”.