truncate - shrink or extend the size of a file to the specified size

To Clear contents of a file with truncate $ truncate -s 0 example.txt

To truncate a file to a specific size $ truncate -s 200K example.txt

To extend file size $ truncate -s +400K example.txt

To reduce file size $ truncate -s -100k example.txt

regards, T.Dhanasekar