shred -n 100 -z -u  filename.which.one.want.to.delete


-u, --remove
truncate and remove file after overwriting
-n, --iterations=N
Overwrite N times instead of the default (25)
-z, --zero
add a final overwrite with zeros to hide shredding


more.. caution



or

wipe filename.which.one.want.to.delete
posted by citadel