If you know the dir of the unix.lst file eg /data, then
and use either the at cmd
http://linux.die.net/man/1/at for a one-off occurrence, or use cron
http://www.adminschoice.com/crontab-quick-reference for repeated occurrences.
If you don't know the location(?), then
Code:
find / -name unix.lst -exec rm {} \;
and use at or cron as above.