Hello,

A typical shell script solution would be

# df /partition |
perl -ne 'exit 1 if (/(\d+)%/ and $1 < 95)' &&
echo "Partition full in $(hostname)" | 
mail -s "$(hostname) - Partition full" xx@yy.com
[download]

But If you want a pure perl solution, then take a look at Filesys::Df and Mail::Send

Other option, if you need a more complete soltution, is using a monitor system like nagios (which was recommended in first comment), munin, or zabbix

Also, please read How do I post a question effectively?.

PD: Updated to be one perl line script