Tilman Kranz – Personal Blog

Utility to search for XDG Desktop Files

3. November 2024 in Administration, GNU/Linux, Programmierung, Technik.

In my previous article Print XDG Desktop Definition for Application i described a way to search the various „applications“ sub-directories of the known XDG data directories for .desktop-files that match certain search criteria.

The short shell script from that article is now available as a commandline utility, including the usual bells and whistles such as option parsing and a manpage. Also, it now supports more exact control over which directives in the desktop files are searched and which are displayed in the search results.

Here is an example searching for any desktop files containing „firefox“ in their „Name“or „Exec“ directives, displaying the „Name“, „Comment“ and „Exec“ directories of each result:

xdg-desktop-search -v -s Exec -s Name -d Name -d Comment -d Exec firefox

The utility is available here:

Gitea project xdg-desktop-searchLast 3 commits: by Tilman Kranz: d27e54cd clarification of json output by Tilman Kranz: e3c2e719 document option --quiet by Tilman Kranz: 0ad7f261 support options --json and --quiet

Getting Alerted on Expiring GPG Keys

3. August 2024 in Administration, GNU/Linux, Programmierung.

GnuPG is a powerful cryptographic tool that enjoys widespread support by F/LOSS mail user agents. However, due to a lack of conventional public key management it is plagued by key-related issues. One such issue is the expiry of GnuPG keys, which often goes unnoticed by affected messaging partners until such time when it actually disturbs messaging between them.

The way user agents handle key expiry situations can roughly be described as follows:

(i) If the GnuPG key of a sender of a message is expired, user agents can not regard it as valid, and the attempt to sign the message using the sender’s key will fail. Once the GnuPG key of a user has expired the user will realize this situation without an external alerting mechanism only when trying to sign a message.

(ii) If the GnuPG key of an intended recipient of a message is expired, user agents can not regard it as valid; the attempt to encrypt a message using an expired key of a recipient will fail. Also, the sending of an encrypted message to multiple recipients, where a subset of the recipients feature expired public keys, can be blocked. Other users will realize this situation once they try to send an encrypted message to the user in question.

In the proposed setup specific GnuPG keys (specified using a list of key IDs) stored in ~/.gnupg are scanned periodically. The scan is repeated daily, at 11 A.M. local time (which can be changed to whatever systemd timers support). The tolerated remaining validity will be set to „more than 30 days“ (this, too, can easily be set to a different value).

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The Noise

15. Januar 2024 in Musik.

Playing the digital synthesizers:

Redirect PulseAudio/PipeWire over TCP/IP network

8. Oktober 2023 in Administration, GNU/Linux, Multimedia, Technik.

If you have two Linux hosts, host1 and host2, both running PulseAudio (or Pipewire with PulseAudio backwards compatibility) and you want host2 to use the speakers on host1, then you can use a PulseAudio TCP server on host1 and a „tunnel sink“ on host2 to do that.

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WordPress Plugin to embed Gitea Repositories

29. September 2023 in Administration, GNU/Linux, Programmierung, Technik.

I ported the WordPress plugin providing shortcodes for embedding Gitlab projects into posts and pages to a Gitea version.

Below is a usage example, displaying the latest 3 commits and the latest release (if any) from repository „linuxfoo-gitea“ on my Gitea instance:

[gitea-show-project url="https://tk-sls.de/git" project_owner=tk-sls.de project_repo=linuxfoo-gitea max=3 releases=latest]

Gitea project linuxfoo-giteaLast 3 commits: by root: 35962433 correct json pat to commit message by root: fccb7dd5 correct message formatting by root: 19f52bfb correct class namesLatest release: v1.0.0

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PiKVM on an OrangePi Zero 2

3. November 2023 in Administration, GNU/Linux, Technik.

The OrangePi Zero 2 H616/1GByte is capable of running PiKVM. I find this an interesting development, because if i only want the KVM functionality, a full-blown Raspberry Pi 4 with all its CPU resources, multiple Gigabytes of RAM and peripheral devices seems somewhat of an overkill. I am aware that the latest official PiKVM, the V4Plus uses a Raspberry Pi Compute Module with 2 GB RAM, but mine is still smaller. 🙂

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Print all indented Lines following a non-indented Line

29. April 2024 in GNU/Linux, Programmierung.

Some configuration and output text formats contain sections like the following:

foo:
   value1
   value2
bar:
   value 3

In this article, two scripts are presented that print all consecutive indented lines that follow a non-indented line that matches a search pattern given by a regular expression.

This means, given the single argument foo and the standard input above, the scripts should