rsync is a replacement for rcp that has many more features. rsync uses the "rsync algorithm" which provides a very fast method for bringing remote files into sync. It does this by sending just the differences in the files across the link, without requiring that both sets of files are present at one of the ends of the link beforehand. This makes rsync a good remote file distribution/synchronisation utility in a dialup PPP/SLIP environment. Note: it requires rsync on the destination machine. There is a Computer Science Technical Report on the rsync algorithm included in the distribution, and is also available as ftp://samba.anu.edu.au/pub/rsync/tech_report.ps