The difference between mathematics and statistics

"Mathematics is about whether the conclusions follow from the assumptions. By contrast, statistics is about whether the assumptions have anything to do with the real world." 

Jay Kadane, Leonard J. Savage Professor of Statistics, Emeritus, Carnegie-Mellon University

rsync

As part of transitioning from using an old desktop to a new desktop (while both are still active), I found the 'rsync' command to be very useful.  Here is the options I ended up using to accomplish my goal of copying over (old) files from the old machine to the new without wiping out any new files on the new machine:

rsync -avzuhP --log-file=/destination/dir/rsync_log.txt -e ssh remoteuser@remotehost:/source/dir /destination/dir/

Here's what the options do:
-a archive
-v verbose
-z compress
-u update  <= Do Not Overwrite the Modified Files at the Destination
-h human-readable
-P progress bar/partial transfers

Note that these options are turned on in '-a' archive mode:
        -r, --recursive             recurse into directories
        -l, --links                 copy symlinks as symlinks
        -p, --perms                 preserve permissions
        -t, --times                 preserve times
        -g, --group                 preserve group
        -o, --owner                 preserve owner (super-user only)
        -D                          same as --devices --specials