Openssl for SAT

For some reason this one has been hard to remember, even when the command is actually easy, so here we go: To query the certificate information, we can run these commands: # Convert the certificate format from DER to PEM. openssl x509 -inform DER -in cert_file.cer -outform PEM -out cert_file.pem # Convert the certificate format and print it to the default output. openssl x509 -inform DER -in cert_file.cer -outform PEM # Print some of the information contained in the certificate and hold # the PEM output.

Mkvmerge Complex Command

It’s common to find video material (wink wink) with a large list of embeded subtitle and / or audio tracks, which on occasion are a pain in the behind for my TV set. To help it work better with these, I remove the audio or subtitle tracks that are not required. And for automate the process (for example, if there are a considerable amount of, ejem, chapters), I use some variants of the following command:

Ext4 Lazy Command

I have been in the necessity of creating large file systems, and I end up using ext4 almost all the time. But in those occasions where the file system is larger than, say, 4TB, I noticed that with the default values, the file system performance was awfully low the first couple of hours after creation. After digging a little, I found out that the issue was due to a lazy initialization feature of the file system, which was very inconvenient when I was in a hurry and I needed to copy a big chunk of files in a short period of time.

Ffmpeg Commands

I’m saving these commands to have an easy way to find them if I need them in the future. For a little context, when I have helped my son with his homework, sometimes I have needed to increase the volume because my cell records them with very low volume (I haven’t found a fix for that), and sometimes I need a fragment of other videos and then to concatenate them. And also, when I started using other more sophisticated video editing tools (like Flowblade), I needed constant framerate videos, which my cell doesn’t do (for some reason).

RAID5 Emergency Recovery

Around 9 years ago I built a machine with the sole purpose of serving as my personal file server. It took me several months to find the parts, and well, I was in a tight budget, but still, I managed to create a little machine with six 3TB hard drives, from which I created a RAID5 array (by software, RAID controllers are pretty expensive). I assembled the array with no spare drive, as I wanted to make the most out of all that space… for, you know, backups (wink wink).