The below simple shell script will check all filesystems and create output file for only filesystems which are more than 80% full and send the log by email.
The below has been checked on AIX7.1 , not too Sure if it works on Solaris. I suppose the -P flag does not work on Solaris.
[code language="bash"]
#!/bin/ksh
df -P | grep -v Capacity | awk '{if ($5 >= 80) {print $5 $6;}}' > /home/root/diskspacelog
mailx -s "DiskSpace for Server Esb1" </home/root/diskspacelog sysadmin@company.com
[/code]