linux

I’m a heavy user of password managers and the DBUS Secret-Service API. The linux kernel has native capability, it’s called the Kernel Key Retention Service, with new syscalls and a userspace command line tool called keyctl. >>> read more

Git uses a SHA1 hash for each file, directory and commit it manages. This hash is a unique identifier for the content of the file or the state of the repository at the time of the commit. >>> read more

Intro A TPM is a hardware component that provides cryptographic functionality for enhanced security on modern computer systems, it stands for “Trusted Platform Module”. >>> read more

Tips and tricks to run Linux on “Dell Latitude 7400” $ dmidecode | grep -i Product Product Name: Latitude 7400 Product Name: 07WDVW Bios By default, the function keys f1 .. are disabled, which is an issue for Alt-F4 (close window), etc. >>> read more

Backup with rclone rclone works well. >>> read more

Despite being required by a number a state organizations, BankId is based on a proprietary protocol and implementation. This pages summarizes the possibilities to run it on Linux. It complements the pages in Swedish by the Ubuntu Sweden Team. >>> read more

Tips and tricks to run Linux on Hewlett-Packard “HP EliteBook Folio G1” (from ‘’dmidecode | grep -i Product’’). Considered distribution: Debian. Bios By default, the function keys f1 .. are disabled, which is an issue for Alt-F4 (close window), etc. >>> read more

To connect to a calendar hosted on Microsoft Exchange from Mozilla Thunderbird, there are several solutions: ExQuilla, Exchange Calendar, TbSync and DavMail. >>> read more

The Recoll desktop search tool can be used to index a maildir directory, for instance that comes from Thunderbird when the maildir format has been activated – user_pref("mail.server.server2.storeContractID", "@mozilla.org/msgstore/maildirstore;1");). Here is how. >>> read more

I have a VPN access that uses the openconnect stack. I want to access a machine on the private network via SSH. However, I don’t want to route all my traffic network through VPN. Here is the solution. >>> read more

I want to create a Github repository with 1,700,000 files. Yes, more than one million files on Git. Even worse, I want to put them in the same directory. Why? Well for creating a scientific dataset of software engineering data: a dataset of all commits of the Apache Repository. >>> read more

Here is a small how-to to backup your data on hubic using a backup tool called duplicity. Done on a Debian box. Your mileage may vary. Howto 1. Install duplicity aptitude install duplicity python-pip # the hubic backend of duplicity requires pyrax pip install pyrax 2. >>> read more

I have recently dig into the *.MSF file of the Mozilla Thunderbird email client. What is the MSF file format? It’s simply a file-based Mork database. Mork is a database format that has been invented by Netscape. >>> read more

I’ve recently come across a hard file-system error: BTRFS critical (device sda2): corrupt leaf, slot offset bad: block=43231330304,root=1, slot=47 It was on my BTRFS file system on top of an SSD (Solid-state drive). >>> read more

I run GNU/Linux on my HP Elitebook 820. Hardware name: Hewlett-Packard HP EliteBook 820 G1/1991, BIOS L71 Ver. 01.20 07/28/2014 (from dmidecode) Graphics Graphics works with the "intel" driver of xorg and the "i915" kernel module. >>> read more

When linking programs, by convention, function "_start" is the entry point. Hence, the linked has to find it somewhere in the object files or libraries that are linked. >>> read more

On Linux, shared libraries (aka dynamically linked libraries) are handled with the ld* set of tools from libc-bin. I've recently encountered some bugs related to this, here are some raw notes on this technology. >>> read more

I've just successfully installed a printer Samsung ML-2525W on two Linux machines (Debian and Ubuntu). Here is what I did. >>> read more

Cups is a printing software system that supports network printing. For instance, if a machine Timoleon is connected to a USB printer, one can access Timoleon over the network to print on the USB printer. The network printing facility also holds for network printers. >>> read more

It is not straightforward to install a Debian server on Amazon EC2. Indeed, Amazon provides as quick start Red Hat Linux, Suse Linux and their own Amazon Linux but not Debian linux. >>> read more

I run GNU/Linux (Debian/Ubuntu) on my DELL Latitude E4200. =====Graphics===== Graphics works perfectly with the “intel” driver of xorg. >>> read more

See also http://www.monperrus.net/martin/performance-of-amazon-elastic-block-store The maximal end-to-end latency of a hard-drive is achieved with accessing a random sector (it includes transfer time). >>> read more

My server regularly stalled, freezed and sometimes crashed under heavy write accesses (open-iscsi on root filesystem). I solved the problem by changing the scheduler and increasing the maximal I/O queue size (nr_requests). >>> read more

I recently encountered performance and reliability problems using iSCSI. One of the most efficient solutions was to set the I/O scheduler to "noop". Noop is the simplest elevator/scheduler in Linux. It is based on FIFO -- first request in, first out. >>> read more

Partition alignment means two things: first that the partition boundaries correspond to physical disk block boundaries (which is straightforward for 512 byte blocks, but not for 128k blocks), second that the partition boundaries correspond to kernel volume blocks. >>> read more

I recently encountered some performance issues using iSCSI. I use the open-iscsi implementation on the client side. After hours of googling and trial and errors, here are some points related to the performance of iSCSI. >>> read more

ExpandAnimations is a LibreOffice/OpenOffice.org extension to expand animations before exporting to PDF. The extension adds a menu entry “Tools>>Add-ons>>Expand animations” in Impress. The generated PDF file is in the same folder as the source document. >>> read more

On a Gnome desktop on Linux, [[http://projects.gnome.org/gnome-power-manager/|gnome-power-manager]] is responsible for handling battery events and physical events (laptop lid closed, power button pressed, etc). The tool ‘’gnome-power-preferences’’ configures it. >>> read more

This document is a complete analysis of a challenging bug related to Xorg, an Intel graphics card and Linux. >>> read more

It’s difficult to backup data if the target filesystem of your backup is vfat (e.g. on the external hard drive of your sister), and the source is ext3. The reason is that vfat has much less features compared to ext3 (e.g. the group information). >>> read more

Rsync is great for backuping data. >>> read more

  Why does my screen blink when I'm using Wine?  Why screen captures don't work with Wink?  How to fix "Unable to save my document" when using Samba/CIFS (e.g. >>> read more

[[http://www.monperrus.net/martin/fonts-test.pdf|This test document produced with OpenOffice shows how type1 font “CM-super/Computer Modern” looks like]]. However this font is “too rich” for OpenOffice, it contains too many different styles (up to 30, cf. below). >>> read more

There is a number of tools to save power on Linux by throttling the CPU(s). Some are daemon based for example cpufreqd, powernowd, powersaved, cpudyn. Some are desktop based for example kpowersave or gnome-power-manager. >>> read more

Here is a solution for automounting usb flash drives / memory sticks on linux using only udev and pmount. add a file ‘’automount.rules’’ in ’‘/etc/udev/rules.d’’. >>> read more

I currently have a Dell Latitude E5400, and run Linux on it. At the moment: `Linux beethoven 6.5.0-28-generic #29-Ubuntu`. >>> read more

1. Problem In this document, we present the different solutions to a classical problem. How to connect to a target machine on a given port, via another machine ? 2. >>> read more