Periodic visit of StackOverflow website

so_visit.sh

#!/bin/bash
# Based on chromium, add the following 2 lines to `sudo crontab -e` 
# 1 1     * * *        rm /tmp/.org.chromium.Chromium.*
# 1 1     * * *        rm -r /tmp/scoped_dir*
# Start a display (https://en.wikipedia.org/wiki/Xvfb)
export DISPLAY=:1
Xvfb :1 -screen 0 1024x768x16 &
PIDD=$!
# Get links
wget -O - https://www.stackoverflow.com | grep -oe "\"\/questions\/[[:digit:]]*\/[[:alnum:]-]*\"" | tr -d '"' | sed '1~2d' | sed "s#^#www\.stackoverflow.com#g" | head -n5 > so_questions.txt
# Visit links
for link in $(cat so_questions.txt); do
  chromium-browser --disable-extensions --disable-plugins ${link} &
  PID=$!
  sleep 20
  kill $PID
done
# Close the display
kill $PIDD