Setup weird resolution for ultrawide monitor on Ubuntu

ultrawide.sh

#!/bin/bash
#
# Set a nonstandard resolution (ultrawide) interactively
#

###
# Define default resolution (and monitor ID if multiple monitors)
# Will be overridden is passed to script as arguments
#
#
width="${1-3440}"	# Width in px, must be /8
height="${2-1440}"	# Height in px, must be /8
fr="${3-50}"		# Refresh rate, must be 50, 60, 75, 85
display="${4}"	# Monitor name (if known, for multiple monitor setup)


###
# Use `cvt` to format the modeline for `xrandr`. Width/height shoudl be a multiple of 8.
# with a regex to remove the comment and leading word "Modeline"
#
#    cvt <width> <height> [refresh=60]
#
modeline="$(cvt $width $height $fr | tail -n1 | sed 's/Modeline //g;s/"//g')"


###
# List all the active monitors and their current resolutions
# with a regex to reduce output to "<monitor> <resolution>".
#
#    xrandr --current
#
monitors="$(xrandr --current|grep ' connected' | sed 's/\(connected\|primary\) //g;s/\([A-Z]\+-[0-9]\) \([0-9]\+x[0-9]\+\)\(.*\)$/\1 \2/g;')"

###
# If $display is defined and not found, abort.
#
# If $monitors returns more than one line (multiple monitor setup), then prompt for a choice.
# Otherwise just use the only active moitor $name
#
if [[ -n "$display" ]]; then
  display="$(echo "$monitors" | grep -o "$display")"
  if [[ -z "$display" ]]; then
    echo "Specified monitor $display was not found. Quitting."
    exit 2
  fi
else
  num_monitors=$(echo "$monitors" | wc -l)
  echo "$num_monitors active monitors detected:"
  if [[ $num_monitors -gt 1 ]]; then i=0
    while [[ $i -lt $num_monitors ]]; do i=$((i+1))
      echo -e "($i) $(echo "$monitors" | head -n $i | tail -n 1)"
    done
    echo -n "Select a monitor [1-$num_monitors]: "
    read -n1 monitor_index
    display="$(echo "$monitors" | head -n $monitor_index | tail -n 1 | cut -d ' ' -f 1)"
  else
    display="$(echo "$monitors" | cut -d ' ' -f 1)"
  fi
fi

echo -ne "\nApply resolution of ${width}x${height}@${fr} to $display? [Y/n]: ";
read -n1 yn 
echo ""
[[ "${yn,,}" == "n" ]] && echo "Quitting." && exit 1

##
# Define a new resolution mode
#
# xrandr --newmode <name> <clock MHz> <hdisp> <hsync-start> <hsync-end> <htotal> [flags...]
#     [+HSync] [-HSync] [+VSync] [-VSync] [+CSync]  [-CSync] [CSync] [Interlace] [DoubleScan]
#

name="$(echo "$modeline" | cut -d ' ' -f1)"
xrandr --newmode $modeline
xrandr --addmode $display $name
xrandr --output $display