Updating with a delta file linux
It offers a large number of options that control every aspect of its behavior and permit very flexible specification of the set of files to be copied.It is famous for its delta-transfer algorithm, which reduces the amount of data sent over the network by sending only the differences between the source files and the existing files in the destination.This option changes this to compare a 128-bit checksum for each file that has a matching size.Generating the checksums means that both sides will expend a lot of disk I/O reading all the data in the files in the transfer (and this is prior to any reading that will be done to transfer changed files), so this can slow things down significantly.rsync is widely used for backups and mirroring and as an improved copy command for everyday use.rsync finds files that need to be transferred using a "quick check" algorithm (by default) that looks for files that have changed in size or in last-modified time.
Without this option, rsync uses a "quick check" that (by default) checks if each file's size and time of last modification match between the sender and receiver.
This option turns off this "quick check" behavior, causing all files to be updated.
This modifies rsync's "quick check" algorithm for finding files that need to be transferred, changing it from the default of transferring files with either a changed size or a changed last-modified time to just looking for files that have changed in size.
Some options only have a long variant, not a short.
If the option takes a parameter, the parameter is only listed after the long variant, even though it must also be specified for the short.This is normally 0 (for an exact match), but you may find it useful to set this to a larger value in some situations.