Check arbitrary PDF file on the web and mail diff from last version if it has changed.

check_and_mail_diff.sh

#!/bin/sh
export PATH=/opt/bin:$PATH
URL=http://example.com/kushitu.pdf
CUR_LENGTH=`curl --head $URL 2>/dev/null | awk '/Content-Length:/ {print $2}'`
cd /home/john/kushitu_checker
if [ $CUR_LENGTH != `cat last_length` ]; then
    curl $URL > kushitu.pdf
    pdftotext -enc UTF-8 -raw kushitu.pdf /dev/stdout | sed 's/^.*現在//g' > kushitu.txt
    diff -U 0 kushitu.txt last_kushitu.txt | nail -A myaccount -s "Room Updates" john@example.com
    echo $CUR_LENGTH > last_length; rm kushitu.pdf; mv kushitu.txt last_kushitu.txt
    fi