cylon/loop led scanner flasher routine in bash

cylon.sh

led0path=/sys/class/leds/$SOME_LED_HERE/brightness
led1path=/sys/class/leds/$SOME_LED_HERE/brightness
led2path=/sys/class/leds/$SOME_LED_HERE/brightness

run=1

led=0
up=1

minled=0
maxled=2
onoff=0

trap doexit SIGINT
doexit() {
  run=0

  # reset all leds to end
  onoff=1
  led=0
  setled
  led=1
  setled
  led=1
  setled
}

setled() {
  if [ $led -eq 0 ];
  then
    echo $onoff > $led0path
  fi
  if [ $led -eq 1 ];
  then
    echo $onoff > $led1path
  fi
  if [ $led -eq 2 ];
  then
    echo $onoff > $led2path
  fi
}

run_cylon() {
  while [ $run -eq 1 ];
  do
    onoff=0
    setled

    if [ $up -eq 0 ];
    then
      led=$((led - 1))
    elif [ $up -eq 1 ];
    then
      led=$((led + 1))
    fi

    if [ $led -ge $maxled ];
    then
      up=0
    fi
    if [ $led -le $minled ];
    then
      up=1
    fi

    onoff=255
    setled

    sleep 1
  done
}

run_loopy() {
  while [ $run -eq 1 ];
  do
    onoff=0
    setled

    if [ $up -eq 0 ];
    then
      led=$((led - 1))
    elif [ $up -eq 1 ];
    then
      led=$((led + 1))
    fi

    if [ $led -gt $maxled ];
    then
      led=$minled
    fi
    if [ $led -lt $minled ];
    then
      led=$maxled
    fi

    onoff=255
    setled

    sleep 1
  done
}

# clear all leds to start
onoff=0
led=0
setled
led=1
setled
led=1
setled

#up=0
#run_loopy

run_cylon