You can pause any program by sending it a
TSTP (polite) or
STOP (forcible) signal. On the terminal you've run
rsync in, pressing Ctrl+Z sends
TSTP. Resume with the
bg command in the terminal or a
It is safe to kill an rsync process and run the whole thing again; it will continue where it left off. It may be a little inefficient, particularly if you haven't passed
--partial (included in
rsync will check all files again and process the file it was interrupted on from scratch.
There may be unusual combinations of options that will lead to some files not being synchronized properly, maybe
--inplace with something else, but I think no single option will cause this.
If you disconnect your laptop and reconnect it somewhere else, it may get a different IP address. Then the TCP connection used by rsync would be severed, so you'd have to kill it and start again. This can also happen if you suspend your laptop and the TCP connection times out. The timeout will eventually filter out to the application level, but it can take a while. It's safe to press Ctrl+C and run rsync again.