Tag: linux

JabRef is a nice utility to manage your paper references. Using it on a high res ...

Xmodmap had been a reliable tool to bring umlauts to the US keyboard layout. However, on modern Ubuntu systems, xmodmap can result in several problems and does no longer work reliably. Using XKB, it is possible to define own layouts that work more reliably. Being able to activate them, seems to change amongst Ubuntu version. Several recom ...

Ubuntu 18.04 does not enable power saving for NVIDIA graphic cards by default. The card will be power-on, even if a secondary graphics chip is the active graphics card. If you selected sudo prime-select intelto ensure that your Intel graphics card is active, then the NVIDIA card will not be disabled. You can use tools like bumblebee to ...

Python’s built-in smtpd was a simple and usable mail server for testing purposes. A simple cli call such as: python3 -m smtpd -n localhost:2525was sufficient to receive your debugging emails. However, there are some problems currently piling up, which are ignored by the python devs. I recently stumbled over the following problem: $ python ...

GitLab wants to be updated on a regular basis. Most of the time, this update is painless. It happens sometimes that the update / upgrade does not work expected and the user is greeted with a 502 error: Such an error can often be removed by reconfiguring the GitLab instance. Stop the GitLab server first sudo gitlab-ctl stopPerform the au ...

Some OpenVPN configurations contain servers that have a IPv6 DNS record configured, but actually do not support establishing connections via IPv6 (e.g. because of a firewall filtering rule). A configuration as shown below can lead to problems: proto udp remote <hostname.somedomain.com>The above configuration lines ask the OpenVPN cl ...

Proxmox comes with extensive firewall rules, which can be configured and managed through the web interface. The setup creates a number of chains, and the rules that are automatically configured can get extensive very quickly. Some parts of the firewall configuration must be done manually. Proxmox for example does not support the configura ...

UEFI laptops sometimes want some massaging before they are willing to boot up the GRUB boot manager. Many postings show different ways to setup the boot manager. Several UEFI-capable devices can be configured using efivars, to store which Boot Manager should be used by default (e.g. the Windows Boot Manager, Grub, …). They then offer an ...

Serial console output can be generated for grub messsages, for the kernel boot process, and the access to the system. Different configuration changes need to be done in order to do that. Grub boot messagesIf you want to see boot messages through the console, you need to pass additional arguments to the kernel through kernel arguments. Thi ...

Most Linux distributions provide their pre-compiled kernels with most options enabled as kernel modules. When self-compiling the kernel, you sometimes miss modules because you did not care to enable all available modules. That can sometimes lead to problems, such as when mounting SMB shares: # mount -t cifs //<myhost>/<myshare&g ...