SWITCHING BETWEEN TV AND LAPTOP DISPLAY
Overview
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I often switch between my TV screen and my laptop. If I'm home, I'm
mostly connected to the TV screen, which I roll around the house on
its cart. My favorite place to put it is right by my bed. I'll sink
into a pile of pillows and furry friends, clacking away at my little
computer tasks for hours. If I'm out-of-doors, then I'm certainly
using the laptops internal display.
I have two screen layouts setup to accomodate these two displays,
`tv.sh' and `lappy.sh'. The first layout only uses the external
display. The second layout only uses the internal display. These
layouts were configured using `arandr', saved inside
`~/.screenlayouts' and made executable. Previously, I would switch
between one and the other by invoking the desired script
manually. This would put me into inconvenient situations: I'd be
connected to the TV, I'd unplugged my laptop while it was sleeping,
and I'd open the lid. The computer'd still have the TV as its primary
display, despite it being unplugged.
I built a shell script, `display.sh', to automatically switch between
the two displays. The script is stored in `/etc/zzz.d/resume', where
it will be executed each time the computer wakes up from its
slumber. Arisen, it will then set the primary display according to
what's available.
The Script
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,----
| #!/bin/sh
| # Tiny script to switch between TV and laptop display.
| # Author: ROYGBYTE
| # Date: September 2023
| # Version: 0.1
| LOG_PREFIX="display.sh: "
| XRANDR_Q=$(xrandr -q)
| # HDMI could be connect but not the primary display. If that's the case,
| # xrandr will report the display number, state, and resolution, as matched
| # for below.
| HDMI_CONNECTED=$(printf "${XRANDR_Q}" | grep "HDMI1 connected" -c)
| PRIMARY_DISPLAY=$(printf "${XRANDR_Q}" | grep "^[[:alnum:]]* connected primary" -o \
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| logger "HDMI Connected: ${HDMI_CONNECTED}"
| logger "${LOG_PREFIX}Primary display: ${PRIMARY_DISPLAY}"
| case "$HDMI_CONNECTED" in
| 0) # No
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Happy helping ☃ here: You tried to output a spurious TAB character. This will break gopher. Please review your scripts. Have a nice day!
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| 1) # Yes
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Happy helping ☃ here: You tried to output a spurious TAB character. This will break gopher. Please review your scripts. Have a nice day!
Happy helping ☃ here: You tried to output a spurious TAB character. This will break gopher. Please review your scripts. Have a nice day!
Happy helping ☃ here: You tried to output a spurious TAB character. This will break gopher. Please review your scripts. Have a nice day!
Happy helping ☃ here: You tried to output a spurious TAB character. This will break gopher. Please review your scripts. Have a nice day!
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| esac
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Improvements
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Eventually, I'd like to build a `udev' trigger to run this script when
the HDMI cable is unplugged. I'd also like to understand why the
strings used to pattern match my case statements (`eDP*', `HDMI*')
don't work if they contain numbers (indeed, `HDMI1' won't match...).