Change default console TERM from vt102 to xterm?

Question

When connecting to the Pi by the serial console, I'd like to have the default TERM be xterm, rather than the current default of vt102:

pi@raspberrypi:~$ echo $TERM
vt102
pi@raspberrypi:~$ tty
/dev/ttyS0

I know I could add this to .bashrc, etc. - but I only want to change the current default, and to otherwise not impact other types of connections.

https://www.debian.org/releases/jessie/i386/ch05s03.html.en seems to indicate that I should be able to add TERM=xterm to the boot parameters - which are at /boot/cmdline.txt. As such, I tried updating the following:

dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait

to:

dwc_otg.lpm_enable=0 console=serial0,115200 TERM=xterm console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait

... and then rebooting, but with no change. Now, http://man7.org/linux/man-pages/man7/bootparam.7.html indicates that this may be a "(useless?) example" (for reasons I don't understand).

Now, I did find /lib/systemd/system/serial-getty@.service, which contains the following:

[Service]
ExecStart=-/sbin/agetty --keep-baud 115200,38400,9600 %I $TERM

... but I can't find where the default $TERM is being defined.

I did add the following here:

    Environment=TERM=xterm

This is working - but it seems that I'm still missing part of the puzzle here, as to where this is defaulting to vt102, or why this can't be set in cmdline.txt.

(Other sources I've already referenced:)

ziesemer · Answer 1 · 2016-08-25T16:03:20.403

Had I read the "Docs" section of the output from systemctl status serial-getty@ttyS0.service, it includes a link to http://0pointer.de/blog/projects/serial-console.html . From there:

serial-getty@.service is responsible for all other terminals, including serial ports such as /dev/ttyS0. It differs in a couple of ways from getty@.service: among other things the $TERM environment variable is set to vt102 (hopefully a good default for most serial terminals) rather than linux (which is the right choice for VTs only), and a special logic that clears the VT scrollback buffer (and only work on VTs) is skipped.

So, this is apparently a hard-coded default. This is also supported by the following:

However, for completeness - I'm still searching for where this is actually coded.

Change default console TERM from vt102 to xterm?

1 Answers1