#!/bin/sh
##
## SCRIPT: 01_rsync_home_AcerDesktop1_to_Seagate1TB_ver1_core.sh    in $HOME/Rsync
##
## PURPOSE: This script uses 'rsync' to backup data files
##          (esp. home directory) --- to an external disk drive.
##
## HOW TO USE: A decktop icon can be used to run the script
##                01_rsync_home_AcerDesktop1_to_Seagate1TB_ver1_RunCoreInTerminal.sh
##             which runs this script in a 'mate-terminal'.
##
##  Alternatively:
##             Open a terminal at home directory, cd Rsync, and run this script ---
##             after the external disk drives are attached and running (powered up).
##
## (It is good to check the current size of the home directory to see if
##  if fits on the external drive.)
##
##
## METHOD OF IMPLEMENTATION:
##
## Reference: Linux Format Magazine #130, Apr 2010, p.105, Answers section
##
## 'rsync' only copies files that are different. With large files that
## have changed, it only copies the parts that have been altered.
## Its main parameters are a 'from' directory and a 'to' directory.
## Example:
## rsync --archive --delete /path/to/source/ /path/to/dest/
##
## The '--delete' option removes files not present on the first directory ---
##     that is, it removes files from the 'dest' directory that are no longer
##     in the 'source' directory.
##
## The '--archive' option causes all file permissions and timestamps to be copied to.
##
## The 'rsync' man page says:
##
##     -a, --archive      archive mode; equals -rlptgoD (no -H,-A,-X)
##
## ***********************************************************************************
## *** The trailing slashes on the directory names are important because they indicate
## *** that you want to sync the contents of the folders. If you omit them, you could
## *** end up copying one directory into another.
## ***********************************************************************************
##
## Since we may be using an MS Windows FAT file system on the 'to' drive,
## we use '--modify-window=1', as explained here:
##
## --modify-window
##	      When  comparing  two  timestamps, rsync treats the timestamps as
##	      being equal if they differ by no	more  than  the  modify-window
##	      value.   This  is  normally  0 (for an exact match), but you may
##	      find it useful to set this to a larger value in some situations.
##	      In  particular,  when  transferring to or from an MS Windows FAT
##	      filesystem (which represents times with a 2-second  resolution),
##	      --modify-window=1 is useful (allowing times to differ by up to 1
##	      second).
##
## Examples:
##  rsync --archive --delete /path/to/source/ /path/to/dest/
##  rsync --archive --delete -v --modify-window=1 \
##        /home/ /media/blaze/Seagate1/home/
##
## Could try -vv instead of -v. Could try -q instead of -v.
##
##
## Created: 2019oct25 from rsync scripts on old 'home-built' computer
## Changed: 2019nov02 Removed '--dry-run' parm.
## Changed: 2020aug24 Removed '--progress' parm.

FROMdir="/home/"
TOdir="/media/blaze/Seagate1TB/home/"
## NOTE: Ending slashes.

if test ! -d "$FROMdir"
then
   echo "
Directory 
   $FROMdir
does not exist. Exiting."
   exit
fi

if test ! -d "$TOdir"
then
   echo "
Directory 
   $TOdir
does not exist. Exiting."
   exit
fi

## You can add '--dry-run' (or '-n') to
## perform a  trial  run  that  doesn't  make  any
## changes (and produces mostly the same output as a real run).
##
## dry-run is most commonly used in	combination  with  the	-v,  --verbose
## and/or  -i,  --itemize-changes options to see what an rsync
## com## mand is going to do before one actually runs it.


## You can try '--progress'
## It tells  rsync  to  print  information  showing  the
## progress of the transfer. This gives a bored user  something  to
## watch.   With  a	modern	rsync  this  is the same as specifying
## --info=flist2,name,progress, but any user-supplied settings  for
## those   info   flags   takes   precedence  (e.g.	"--info=flist0
## --progress").
##
## While rsync  is  transferring  a	regular  file,	it  updates  a
## progress line that looks like this:
##
##  782448  63%  110.64kB/s    0:00:04
##


set -x

## USE ONE OF THE FOLLOWING for the first line of the cmd.
##
##    rsync --dry-run --progress --stats \
## OR
##    rsync --progress --stats \
## OR
##    rsync --stats \

rsync --stats \
   --archive --delete -v --modify-window=1 \
   "$FROMdir" "$TOdir"

read PRESS_ANY_KEY_toContinue
   
set -