Below are few commands to empty content of a file that already exists in a directory.
When I was trying to connect to s3bucket from my local it failed and the reason I found was my system time was bit behind.
Today When I was importing large database I was getting error that there is not enough space after half of the database was imported. When I checked space it was showing 100% used. Even though I had dynamic space allocated, it was not increasing beyond 37GB. After going through few forums I managed to combine all tips & tricks and apply them to increase my oracle virtualbox ubuntu main partition.