transfer large amount of files - e.g. a large multi-terabyte directory with many subdirectories between physical drives

large-xfer.sh

# -f    If the destination file cannot be opened, remove it and create a new file, without
#       prompting for confirmation regardless of its permissions.  (The -f option overrides
#       any previous -n option.)
# -p    Cause cp to preserve the following attributes of each source file in the copy: mod-
#       ification time, access time, file flags, file mode, user ID, and group ID, as
#       allowed by permissions.  Access Control Lists (ACLs) and Extended Attributes (EAs),
#       including resource forks, will also be preserved.
#
#       If the user ID and group ID cannot be preserved, no error message is displayed and
#       the exit value is not altered.
#
#       If the source file has its set-user-ID bit on and the user ID cannot be preserved,
#       the set-user-ID bit is not preserved in the copy's permissions.  If the source file
#       has its set-group-ID bit on and the group ID cannot be preserved, the set-group-ID
#       bit is not preserved in the copy's permissions.  If the source file has both its
#       set-user-ID and set-group-ID bits on, and either the user ID or group ID cannot be
#       preserved, neither the set-user-ID nor set-group-ID bits are preserved in the
#       copy's permissions.
#
# -R    If source_file designates a directory, cp copies the directory and the entire sub-
#       tree connected at that point.  If the source_file ends in a /, the contents of the
#       directory are copied rather than the directory itself.  This option also causes
#       symbolic links to be copied, rather than indirected through, and for cp to create
#       special files rather than copying them as normal files.  Created directories have
#       the same mode as the corresponding source directory, unmodified by the process'
#       umask.
#
#       In -R mode, cp will continue copying even if errors are detected.
#
#       Note that cp copies hard-linked files as separate files.  If you need to preserve
#       hard links, consider using tar(1), cpio(1), or pax(1) instead.
#
# -v    Cause cp to be verbose, showing files as they are copied.
#
# per: http://stackoverflow.com/a/5345078/227260
# 2>&1 to redirect STDOUT AND STDERR to the file (works in bash, zsh)

echo "running large-xfer.sh" >> large-xfer.log

function doCopy() {
    cp -f -p  -R -v $1 $2 >> large-xfer.log 2>&1
}

function doMove() {
    mv -f -p  -R -v $1 $2 >> large-xfer.log 2>&1
}