Daniel Lange's blog (Entries tagged as keyboard)

Resizing Xterm fonts with Ctrl+ and Ctrl+

nospam@example.com (Daniel Lange) — Mon, 12 Jan 2026 12:15:00 +0000

Xterm misses the convenient option to resize the fonts with Ctrl+<plus> and Ctrl+<minus> like xfce4-terminal or gnome-terminal do out of the box.

This feature can be added on Debian systems by dropping a configuration snippet into /etc/X11/Xresources/x11-xterm-fontsize:

! Allow XTerm font size to be changed with Ctrl+<plus> and <minus>
XTerm.vt100.translations: #override \n\
Ctrl <Key> minus: smaller-vt-font() \n\
Ctrl <Key> plus: larger-vt-font()

Any new X session will inherit this configuration and Ctrl+<plus> and Ctrl+<minus> will work to adjust the font size (and taking the window size along).

The font sizes that Xterm iterates through can be viewed on the Ctrl-<right click> context menu:

NB: The context menu allows to switch the fonts on systems where the above snippet has not (yet) been installed. So good enough for a one-off.

Credits: Stack Overflow/Ask Ubuntu, Matthew Hoener.

Irssi update to 0.8.19 from Debian jessie-backports may break enter / carriage return key / ↵ key

nospam@example.com (Daniel Lange) — Fri, 06 May 2016 08:30:00 +0000

Updating to irssi 0.8.19 (which is a mainly a bugfix release to 0.8.18) proved a real issue. The enter key (return key) stopped working. Ctrl-J still worked but that's way too annoying to remember after each line. Searching the github issues turned up #327 Numeric keypad "Enter" key stopped working which didn't help much. Digging deeper it shows the irssi devs enabled "App key" mode in these releases which causes so many issues, they had to implement a switch to turn it off again.

So a hopeful: /set term_appkey_mode off followed by Ctrl+J, remember ...

and ... nothing changed.

So finally, after more digging and a quick consideration to go back to irssi 0.8.17 on Debian stable (Jessie) ...

/bind ^M key return

Yes, irssi 0.8.19 wants to be told what the enter key is, like, by default. Duh.
No idea what caused this in my configuration, I've been using irssi for more than a decade so much cruft has accumulated in my .irssi/config but ... in case you run into this as well, hopefully I helped you save a morning for something better to do.

If you want to fumble this into your .irssi/config (e.g. because Ctrl-J does not work for you):

keyboard = (
  [...]
  { key = "^M"; id = "key"; data = "return"; },
  [...]
);

Fixing FreeNX / NoMachine NX keyboard glitches (e.g. ALTGr)

nospam@example.com (Daniel Lange) — Sun, 10 May 2009 11:44:18 +0000

There is a add-on technology to X or VNC called NX by an Italian company called NoMachine. It's quite useful as it speeds up working on remote desktops via slow network connections (i.e. DSL pipes) substantially.

The libraries that implement NX are released under GPLv2 by that company. A server wrapping up the libraries' functionality is available as closed source from NoMachine or as a free product (GPLv2 again) by Fabian Franz, called FreeNX.

FreeNX itself is amazing as it is written in BASH (with a few helper functions in C). It's also able to mend some of the shortcomings of the NX architecture. E.g. stock NX requires a technical user called "nx" to able to ssh into the NX server with a public/private keypair. FreeNX can work around that for more secure set-ups.

One issue I bumped into quite regularly with Linux clients and Linux hosts from different distributions/localisations is that the keymaps are not compatible. This usually results in the ALTGr key not usable, so German keyboard users can't enter a pipe ("|"), tilde ("~") or a backslash ("\") character. Also the up and down keys are usually resulting in weird characters being pasted to the shell. Now all of that makes using a shell/terminal prompt quite interesting.

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