How do I copy just the files that have changed?

[MichaelD]

I run WinXP. I have an internal HD that I backup to...it's my "filing cabinet" essentially. I also have an external USB HD that I copy my internal drive to about once a month.

I've just been overwriting ALL the files on the external w/the files from the internal. When you're talking 400+GB of data, that takes awhile.

Is there a way (Command line?) to copy ONLY the files that have CHANGED without copying everything? Script, maybe? I'm a script n00b so obviously I can't figure it out myself.

Thanks for the help. 🙂

 

[Crusty]

You can always use rsync to do it, but that requires either a cgywin install in windows as I don't think there is a straight forward Windows port of it.

Failing that, im sure there are tons of other backup programs to do that, hopefully someone else will know some good ones 🙂

 

[drebo]

Use GoodSync for a free differential file syncronization program. I use it all the time. It's great.

 

[Smilin]

Easy.

Use xcopy with the /M switch.

Anytime a file gets updated the archive attribute will get set. The /M switch will copy archive files then clear the archive attribute. The net result is basically like a incremental backup.

If you want to copy all archive-bit files without resetting the archive bit use the /A switch instead. The net result is basically like a differential backup.

xcopy with the /y switch (suppress overwrite prompt) is basically like a full backup.

 

[MichaelD]

Thanks much, Drebo and Smilin. :beer:

@Smilin: Will those switches messing w/archive bits mess up my files? Will it change anything about them? Don't want to mess up my data. Thanks!

 

[VinDSL]

Robocopy is your friend!

Sorry, I'm short on time...

Here are some switches for you.

They're self-explanatory! 😉

 

[MichaelD]

Originally posted by: VinDSL
Robocopy is your friend!

Sorry, I'm short on time...

Here are some switches for you.

They're self-explanatory! 😉

Wow, I've never even heard of Robocopy. 😱 It looks exactly like what I need. Nice link! Thanks man! :beer:

 

[Smilin]

Originally posted by: MichaelD
Thanks much, Drebo and Smilin. :beer:

@Smilin: Will those switches messing w/archive bits mess up my files? Will it change anything about them? Don't want to mess up my data. Thanks!

Nope it doesn't touch the data. The archive bit was designed for backups (archives) which is pretty much what you're doing. It's a flag just like system, read-only, and hidden.

When anything writes to a file the archive bit gets set indicating it needs to be archived. When a backup program comes along and copies it, it clears the bit to signify it's been backed up.

Robocopy is great but probably some overkill for what you are doing. It first came out way back in the NT days and much of the functionality has been added to xcopy now. There are still some crazy things it can do but it's rare to need them.

 

[MichaelD]

Thanks for the detailed explanation, Smilin; it's good to know the nuts and bolts of the process. I think I'll try Xcopy first and see if it does the job for me. The less programs/utilities I have installed, the better. Built-in utils FTW.