I had the need to concatenate several PDFs into just one. A bunch of music scores for my band I want to keep on the ipad as a single file instead dozens of separate files. I was looking for options and there are a lot of them: pdfunite, pdftk, ImageMagic’s convert (convert inputFile1.pdf inputFile2.pdf outputfile.pdf should do it, but it didn’t worked for me. Even it’s supposed you can select the pages you want for any file: convert inputFile1.

So long!. I know, 2020 has been such a strange year. For me, it also was the first time (yes, in my life) I switched to another company. Coming from being self-employed on my own company, it was a great challenge but I’m really happy about it. Even I had to be forced to keep my mind fully in focus for work. Anyway: I want to talk about my new security setup for internet applications.

I recently got a pair of cheap HyperFido keys. Some of them are as cheap as 5,5€ on Amazon but you can get others which maybe have better quality. Also, there are another keys which have support for bluethooh, NFC, and other features that can be very useful. Anyway. That keys don’t work out of the box in Linux as they are not recognized as the proper hardware type by linux kernel, but the solution is very easy to implement.

In postgresql it’s pretty easy to show which queries can be optimized on your application. Or, at least, which queries are more time consuming. Just execute the following statement on your database ALTER DATABASE myDatabase SET log_min_duration_statement = 5000; to show which queres takes more than 5 seconds. Output will go to your postgresql system log. More information about Postgresql performance

It’s a common task: “Please, add my public ssh key to that host”. And I usually get the key, copied it to buffer, ssh to the remote host, cd .ssh and finally I do a cat - >> authorized_keys and paste the key. But you can do it in just one single line: cat new_key.pub | ssh myRemoteHost "cat >> ~/.ssh/authorized_keys" That’s all!