Place this in your ```~/.bash_aliases``` file.

zoom_xfce4_terminal.sh

CONFIG=~/.config/xfce4/terminal/terminalrc

# Prevent terminal window losing focus
# sudo apt-get install xdotool wmctrl
get_winid() {
  xwininfo -name "$(xdotool getwindowfocus getwindowname)" | \
    grep 'Window id:' | \
    cut -d" " -f4
}

restoreFocus() {
  wmctrl -i -a "$1"
}

zi() {
  #set -xv
  #wind_id=`get_winid`
  SIZE=`grep 'FontName' $CONFIG | awk '{print $NF}'`
  if [[ "$1" ]]; then
    steps=$1
    NEWSIZE=$((SIZE + steps))
  else
    NEWSIZE=$((SIZE + 2))
  fi
  #echo "old size $SIZE, new size $NEWSIZE"
  REGEXPR="s/FontName\(.*\)${SIZE}$/FontName\1"$NEWSIZE"/g"
  #echo "$REGEXPR"
  sed -i "$REGEXPR" $CONFIG
  #restoreFocus "$wind_id"
  #set +xv
}

zo() {
  #set -xv
  #wind_id=`get_winid`
  SIZE=`grep 'FontName' $CONFIG | awk '{print $NF}'`
  if [[ "$1" ]]; then
    steps=$1
    NEWSIZE=$((SIZE - steps))
  else
    NEWSIZE=$((SIZE - 2))
  fi
  #echo "old size $SIZE, new size $NEWSIZE"
  REGEXPR="s/FontName\(.*\)${SIZE}$/FontName\1"$NEWSIZE"/g"
  sed -i "$REGEXPR" $CONFIG
  #restoreFocus "$wind_id"
  #set +xv
}

z() {
  #set -xv
  #wind_id=`get_winid`
  SIZE=`grep 'FontName' $CONFIG | awk '{print $NF}'`
  if [[ "$1" ]]; then
    NEWSIZE=$1
  else
    NEWSIZE=9
  fi
  #echo "old size $SIZE, new size $NEWSIZE"
  REGEXPR="s/FontName\(.*\)${SIZE}$/FontName\1"$NEWSIZE"/g"
  sed -i "$REGEXPR" $CONFIG
  #restoreFocus "$wind_id"
  #set +xv
}