Let’s imagine that we want reduce the size of an LVM partiton (logical volume) by 30 GiB.

They are 6 steps to follow:


Today I downloaded and tried to run Lossless-cut on Debian 10 Buster system, and I got this error:

$ ./LosslessCut-linux.AppImage
[479026:0502/185909.649080:FATAL:setuid_sandbox_host.cc(157)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now. You need to make sure that /tmp/.mount_lossle3kkVRT/chrome-sandbox is owned…


First install ddclient:

sudo apt install ddclient

This will open its shell-based UI. Put whatever, as we’re going to change that later.

Edit /etc/ddclient.conf as follow:

## OpenDNS.com account-configuration
use=web, web=myip.dnsomatic.com
login=<opendns e-mail>
password='<opendns password>'
<Name of the network you set up in OpenDNS>


$ curl -s https://syncthing.net/release-key.txt | sudo apt-key add -
$ echo "deb https://apt.syncthing.net/ syncthing stable" | sudo tee --append /etc/apt/sources.list
$ sudo apt update
$ sudo apt install syncthing

Then run it to generate a default configuration:

$ syncthing

To make possible to access to Syncthing from outside, change this line in .config/syncthing/config.xml :




Note: I recommend to change the port also!

Run again Syncthing:

$ syncthing

Open Syncthing in your browser:

https://<your server IP>:8384

Warning: Make sure that you connect with HTTPS!

You can ignore your browser’s HTTPS warning.

Now, IMMEDIATELY set a password for Syncthing in Settings — >GUI. Also check “Use HTTPS for GUI”.


I just had this error:

Removing network docker_default
WARNING: Network docker_default not found.
Status: Image is up to date for certbot/certbot:latest
docker: Error response from daemon: driver failed programming external connectivity on endpoint certbot (8149e65ee1ff0152bed82aab1f48fda3a1ecf802e1f215946e5a875bc9c47654): (iptables failed: iptables --wait -t filter -A DOCKER ! -i docker0 -o docker0 -p tcp -d --dport 443 -j ACCEPT: iptables: No chain/target/match by that name.
(exit status 1)).

It happen if you update your iptables rules while Docker is open. Actually it can be solved easily.

Just restart Docker:

sudo systemctl restart docker

Hope it helped you!

First install Node.js :

cd /opt
git clone https://github.com/Splode/pomotroid.git
sudo chown -R authmane512:authmane512 pomotroid
cd pomotroid
npm build

No need to add pomotroid to /usr/bin , Pomotroid will automatically ask for that.

EDIT it doesn’t work:

./build/Pomotroid\ 0.6.2.AppImage
[79770:1215/204145.680694:FATAL:setuid_sandbox_host.cc(157)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now. You need to make sure that /tmp/.mount_PomotryTAOOn/chrome-sandbox is owned by root and has mode 4755.
fish: “./build/Pomotroid\ 0.6.2.AppIma…” terminated by signal SIGTRAP (Trace or breakpoint trap)

I had today a strange error. If I mounted a remote folder with SSHFS, the owner was wrong:

$ whoami
$ la /media/mycloud/
total 152K
drwxr-xr-x 1 <not authmane512> <not authmane512> 4.0K Nov 21 14:43 ./

To solve this problem, I use the parameters -o uid= and -o gid= .

To know what is my user ID and my group ID, I run:

$ id
uid=1000(authmane512) gid=1000(authmane512) groups=1000(authmane512),24(cdrom),25(floppy),27(sudo)


$ sshfs -o reconnect,uid=1000,gid=1000  mycloud:/home/myfiles /media/mycloud
$ la /media/mycloud/
total 152K
drwxr-xr-x 1 authmane512 authmane512 4.0K Nov 21 14:43 ./

I had this error:

$ ls
Corriges unsorted/ FA/ FA calcul litt
Corrig??s 11H.zip

Output of locale :

$ locale
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory

To solve this problem temporarily run:

$ export LC_ALL="en_GB.UTF-8"
$ ls
Corriges unsorted/ FA/ FA calcul litt
Corrigées 11H.zip

To solve it permanently, run:

sudo dpkg-reconfigure locales

Then logout and login back (even if some errors may have already gone).

Simply install that package:

sudo apt install ntfs-3g

That’s all!


In this tutorial, I will show you how you can encrypt or decrypt data in Javascript with TweetNaCl.js. It is a port of NaCl (Networking and Cryptography library) to Javascript. We’ll also see how to store the encrypted data in files.

To install TweetNaCl, do the following:

npm install tweetnacl

We also need tweetnacl-util to encode/decode in UTF-8 and Base64:

npm install tweetnacl-util

Note that tweetnacl-util is bad, they reversed names of functions to encode and decode UTF8…

Unfortunately, this port of NaCl don’t provide a key derivation function, so we’ll use scryptsy :

npm install scryptsy



Thanks for reading!

Authmane Terki

Online maths tutor and developer — mathcam.ch

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