Short but useful tip:
If you want to test if a port is open on Linux (e.g. all firewalls were opened) but you don’t have the listening application installed yet, you can use nc/netcat.
On the server side do:
On the client side you can now connect to the listening port:
This is basically a telnet chat, so you can send strings which should then be received on the other side. If you want even more good uses for netcat, I recommend this blog post.
As I’m working with my Raspberry Pis again, I wanted to reactivate the wallets of crypto currencies I used to mine some time ago. The Pi is not very potent, so only Proof-of-stake coins qualify. For me those are Blackcoin, Mintcoin and Reddcoin all of which I wanted to run on the Pi. Of course I needed the headless version, I’m not using X11, not even speaking of QT. So here is the TL;DR for compiling the blackcoind, mintcoind and reddcoind on Raspbian. It is probably the same for every other Debian derivate and most altcoins, independent of architecture or name. I’m taking Blackcoin for my example:
That’s it. Now drink a coffee or - in my case with the original Raspberry Pi Model B, take a long nap (5 hours compile time). Afterwards you are free to enjoy your own brand new blackcoind.
A small tip while I’m playing with my Raspberry Pi, Docker and the love child of both, Hypriot:
If you want to mount an image of a block device you created with dd, you might encounter the problem that you don’t know where the partitions start. In past times I used either offsets or kpartx for that. Today I found an easier way on superuser, the losetup tool. With losetup the process is really easy. Just associate your image file with a new loop device mount the corresponding partition:
If you’re done, umount and detach the file from the loop device:
It seems the –partscan function is fairly new and not every Linux distro has such a new losetup version. Then you can either upgrade the version or do it as our ancestors did, utilizing offset or using kpartx.
I had the big task of explaining my mother how to add members to a TextSecure group. As she’s no IT native, she often forgets and tends to be slow on the uptake. That’s why I created a picture howto for it. It’s not polished in any way, but perhaps I can help someone who has met a similar challenge.