cron safe bash script for checking URLs (pages) for updates

I needed to monitor a government data source for updates. Of course being a government institution, they haven't caught on to the RSS/ATOM concept so the normal tools for this will not work. (There really should be a "Google Alert" option for this.) This is the simple bash script I whipped up to serve the purpose.

#!/usr/bin/env bash
# pagecheck.sh - intended to be call via crontab (call with -v for verbose) ##

# If you want to override the standard temp dir, define it here.
export TMPDIR=$HOME/tmp

# List the pages you wish to check below, one per line, between the EOFs
pages=`cat < < EOF
http://www.gadoe.org/pea_communications.aspx?ViewMode=0 
http://www.gadoe.org/pea_communications.aspx?ViewMode=1&obj=1635
EOF
`
for page in $pages; do
    hash=$(echo "$page"|md5sum |sed 's/[^a-z0-9]//gi')
    basename=$(basename $0)
    name=$basename.cache.$hash
    file=$TMPDIR/$name
    diff=$TMPDIR/$basename.diff
    [[ "$1" = "-v" ]] && echo "Checking $page"
    if [[ ! -f "$file" ]]; then
        file=$(mktemp -t $name)
        echo "Creating cache $file ..."
        curl --stderr /dev/null "$page" > $file
    else
        [[ "$1" = "-v" ]] && echo "Checking against cache file $file ..."
        curl --stderr /dev/null "$page"| diff -u $file - > $diff || (echo -e "Found a change in $page\n"; cat $diff; echo "")
        patch $file $diff
    fi
done
[[ "$1" = "-v" ]] && echo "Done!"

# vim:ft=sh

And to run this script every hour, I modify my crontab (via: "crontab -e") and make it look like so:

MAILTO=me@mydomain.com
#min    hour    day/m   month   day/w   command
0       */1     *       *       *       /home/rbronosky/bin/pagecheck

# vi:syntax=crontab:ts=8:tw=0 

Enjoy! I hope someone else finds this useful.