Shrink or extend the size of a file to the specified size.

# To set a size of 10 GB to an exsting file, or create a new file with the specified size:
truncate -s <10G> <filename>

# To extend the file size by 50M, fill with holes (which reads as zero bytes):
truncate -s +<50M> <filename>

# To shrink the file by 2GiB, by removing data from the end of file:
truncate -s -<2G> <filename>

# To empty the file's content:
truncate -s 0 <filename>