Hello there!

I would like to know if there is a way to tell my distro (Mandriva One 2007) that I want my USB stick to synchronize a certain folder it contains with a certain folder my HD contains. By synchronizing, I mean that I want files, for instance on the USB stick, that have been edited more recently that those on the HD replace the one existing on the HD. I guess it is possible with Cron, but since I am a not yet a pro with the shell commands, I need some help out there.

If you need more clarity, just tell me.

Thanks in advance!

P.-S. By the way, I hope my English is not too bad, I'm from Quebec, the last fortress of French in Canada, meh.

You can use the rsync command to synchronize folders.

rsync -a source --delete destination

The source and destination represents the paths to your folders.

An example:

rsync -a /mnt/sda1/ --delete /home/user/some_dir

-a will archive all folders and subdirectories
--delete will synchronize folders

The /mnt/sda1 is a usb stick, it will have the recent updated files. Rsync will make a duplicate copy of
/mnt/sda1 to /home/user/some_dir

Use the --delete with caution! This will delete files
from the destination path not found in the source path.

In other words, files updated or deleted from the source will be applied equally to the destination.

Practice first.

You can do the same thing without the --delete option. This will keep the files on both sides updated, but nothing is deleted.

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Thanks a bunch. I still have one more question, though. Can I have Cron do this each time I plug in the USB stick?

No. Cron does not detect nor mount devices. Cron is a schedular program. You can use cron to schedule
tasks at specific times. You can use cron to do
synchronizing of your usb stick and folder at certain
time schedules. Just make sure the usb stick is mounted before cron runs its schedule time.

Do a google search on linux cron setup or how to.

Hope it works

Thanks guys!

I fould something that would permit me to do what I want. There are udev rules that makesa backup of all the data on a USB stick to the HD, it seems. I can meld the rsync feature with this so it will do it automatically.

See ya!

Hey guys. I came to this thread seeking the same advice: How to SYNC USB drive folder with system drive folder, always preferring newest files. After playing with rsync, -av will not SYNC preferring newest. It will always overwrite dest files with source files-- even if dest files are newer. The two commands I run to SYNC two folders preferring newest are:

rsync -avuz source/ dest/
rsync -avuz dest/ source/


This will assure both folders are in sync with latest files always being used.

NOTE: the trailing '/' is also important!

'avuz' sounds like something. I guess you could also remember 'zuva'

Hope this helps.

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There is a nicely convenient tool called usbsync which has specially been desgined for the purpose of keeping a usb flash drive in sync with multiple Unix hosts.

Check it out at http://klingspor-thueringen.de/usbsync

Cheers,
welle

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The post is more than two years old...

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Good call, cause rsync, udev, and usbsync are no longer useful tools... oh... wait.

welle: Thanks for the tip! I was going to script something myself, but usbsync's working great.

Here's a sample udev rule (/etc/udev/rules.d/90-local.rules) in case anyone wants to automate running a script on plugging in a USB HDDNotes:

1. Values used in ATTR{*}== and ATTRS{*}== can be found when the device is plugged in by running udevadm info -a -p /sys/block/sdc/sdc1, replacing sdc and sdc1 with appropriate values.
2. All the ATTRS{*}== values must be taken from a single parent device.
3. The called script can determine the /dev/sd* device file to use in mounting by
   Code:

   maj_min="$(cat "/sys$devpath/dev")"
   buf="$(ls -l "/dev/block/$maj_min")"
   dev_file="/dev/${buf##*/}"
   mount $dev_file $mountpoint

4. When udev runs such a script it captures stdout (and stderr?). For debugging they can be redirected to somewhere visible.

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