It turns out it's a known issue: https://gitlab.freedesktop.org/xdg/xdg- utils/-/issues/10.
** No longer affects: kubuntu-meta (Ubuntu) -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xdg-utils in Ubuntu. https://bugs.launchpad.net/bugs/1970594 Title: "xdg-settings check default-web-browser something.desktop" fails in Kubuntu 22.04: Bad substitution Status in xdg-utils package in Ubuntu: Confirmed Bug description: I'm reporting this issue from stock Ubuntu, but the problem is observed only in Kubuntu (can be reliably reproduced in a Kubuntu 22.04 VM). The version of xdg-utils is identical. This problem was initially reported on the snapcraft forum: https://forum.snapcraft.io/t/firefox-wont-set-as-my-default- browser/29708. $ xdg-settings check default-web-browser firefox_firefox.desktop /usr/bin/xdg-settings: 734: Bad substitution The offending line is: if [ x"!" == x"${browser:0:1}" ]; then If I modify /usr/bin/xdg-settings in place to set the interpreter to /bin/bash on the first line of the script, the problem goes away. ProblemType: Bug DistroRelease: Ubuntu 22.04 Package: xdg-utils 1.1.3-4.1ubuntu1 ProcVersionSignature: Ubuntu 5.15.0-27.28-generic 5.15.30 Uname: Linux 5.15.0-27-generic x86_64 NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair ApportVersion: 2.20.11-0ubuntu82 Architecture: amd64 CasperMD5CheckResult: unknown CurrentDesktop: ubuntu:GNOME Date: Wed Apr 27 11:21:31 2022 InstallationDate: Installed on 2020-09-16 (587 days ago) InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Alpha amd64 (20200910) PackageArchitecture: all SourcePackage: xdg-utils UpgradeStatus: Upgraded to jammy on 2022-03-19 (38 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xdg-utils/+bug/1970594/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
