RSYNC (Remote Sync) and SCP (Secure Copy) are both commands in UNIX and Linux-based systems that are used for transferring files between computers. Although they serve similar purposes, they do not function in quite the same way.
RSYNC, as the name implies, is primarily used for synchronizing files and directories from one location to another while minimizing data transfer using its delta-transfer algorithm, which only copies the part of files that have been changed, rather than copying an entire file even if only a small part has been modified. This mechanism makes RSYNC particularly advantageous for performing backups and mirroring data.
SCP, on the other hand, originated from the SSH (Secure Shell) family, thus, it transfers files securely by encrypting both the file data and commands. However, it does not support the incremental copy feature inherent to RSYNC, which means it copies the entire file even if a few changes were made, making it slower than RSYNC for the recurring copy where only a small portion of the source has changed.
Beyond the files/directories synchronization, RSYNC also provides options to preserve file permissions, ownerships, and timestamps during the synchronization process, and it also allows you to exclude certain files from synchronization using patterns, which are not supported by SCP.
In terms of syntax, SCP replicates the syntax of the UNIX CP (copy) command, which makes it a little more straightforward for those familiar with UNIX systems (as the syntax is `scp source_file_name username@destination_host:destination_folder`). RSYNC’s syntax, while not much more complicated (\`rsync options source destination), offers the flexibility of more advanced features through the use of options.
In summary, SCP is best used when you want to transfer a few files securely from one computer to another, particularly if the files do not already exist on the destination machine. RSYNC, on the other hand, is more appropriate when you need to keep directories synchronized between machines, especially when dealing with large amounts of data or performing frequent backups.
References:
1. Shah, P. (2020). Rsync vs SCP | 7 Most Valuable Differences You Should Know. (Educba.com).
2. Rsync vs scp Speed/Performance – BashWorkz. (2016). Bashworkz.com.
3. Rsync (Remote Sync): 10 Practical Examples of Rsync Command in Linux.(2017). Tecmint.com
4. SCP Linux – Securely Copy Files Using SCP examples. (2009). Like Geeks.
