Automating backup of Flash drives 
posted in the wee hours by Constantinos. Filed under Code, OS X 
This post was originally published in 2007
The tips and techniques explained may be outdated.
I have a lot of my critical work on a few flash drives which I carry around with me constantly, mainly because I work on a number of machines and would like to have a central repository of my work. After losing one of the drives recently though (bound to happen sooner or later), I looked further into automating the backup process (I had lost about 2 days of work). That’s when I stumbled accross this hint on macosxhints.com, but the script didn’t exactly fulfil what I had imagined my automated process to do.
Ideally, the automated backup process would have these features:
- Not require installation of any third party app
- Have the ability to somewhat customize the backup script for each thumb drive
- Have the backup script silently run whenever the thumb drive is mounted
- Require little to no set up for each new thumb drive that I want to backup
- Support spaces in Volume names
- Not try to backup the boot drive under any circumstances (don’t ask…)
Updated 2007-03-10: I updated the backup script to include automated handling of archives, and keeps an arbitrary number (specified in the preferences of the script) of incremental archives using rsync's --link-dest parameter, as recommended by John in the comments. This creates what functionally amounts to FULL backups, but with a fraction of the space needed for an actual tar backup. Also it can be configured to keep at most one backup per day, or with minor editing at most one backup for any period of time.
Updated 2007-03-18: I've created a second script which can be used as a drag-n-drop solution. Simply save the script as an application bundle, save it somewhere handy, and drag it to your dock. Now you can drag your thumb drive on the script which will perform the backup, and then eject your drive!
Updated 2008-03-10: Folder action modified to work with Leopard. Well, more like hacked at this point, but it seems to work.
Now to satisfy the first parameter, using Do Something When was out of the question, even though it seems like a good piece of software. That’s when I turned to Fodler Actions, and found this hint again on macosxhints.com. I then proceeded to read the Apple-published Folder Action for automating backups (which, again, didn’t do quite what I wanted), so I came up with this:
A folder action that scans the root folder of the mounted volume, and looks for (one of) a specified file name.
property backup_script : "rsync.app" (* add/change this string to match the name of your script *) on adding folder items to this_folder after receiving these_volumes tell application "Finder" try set the volume_list to every file of this_folder (* go through all entries in /Volumes/ *) repeat with i from 1 to number of items in volume_list set this_item to the original item of item i of volume_list if the kind of this_item is "Volume" then set this_disk to (this_item as alias) (* is this item the newly mounted disk? *) if this_disk is in these_volumes then (* iterate through all files in the root of disk *) set searchCmd to "ls -d " & quoted form of POSIX path of this_disk & backup_script (* check to see if a backup script is available *) set searchResult to "" try set searchResult to do shell script searchCmd end try (* run the backup script *) if (searchResult starts with "/Volumes") then set backupFile to POSIX file searchResult as alias open backupFile end if end if end if end repeat on error error_message number error_number if the error_number is not -128 then display dialog error_message buttons {"OK"} default button 1 end if end try end tell end adding folder items to |
Download this script
If you already know how to apply folder actions, just save the script above and apply it as a folder action to the /Volumes/ folder. If you don’t know (or don’t remember) how to do that, re-iterating the instructions from this Apple page, follow these steps to do it:
- Copy the above code in Script Editor
- Save it as a script in
/Library/Scripts/Folder Action Scripts/, and give it a descriptive name - In Finder, click Go -> Go to Folder (or just press cmd-shift-G), and type
/Volumes/. - Launch the
Folder Actions Setuputility (probably located in/Applications/Apple Script/folder) - Click the Add Folder Action (round plus) button at the bottom left
- Drag the small folder icon from the Finder window title bar into the Choose Folder sheet dialog, and click ok.
- From the dialog that comes up, chose the script you just saved.
- You’re done.
Alternatively (or additionally), you can save this script as an application bundle, save it somewhere handy, and drag it to your dock. When you drag a thumb drive on this application the backup process will start, and as soon as it's done the drive will eject.
property backup_script : "rsync" (* add/change this to match the name of your script *) on open dropped_item set this_vol_alias to (dropped_item as alias) try tell application "Finder" if the kind of this_vol_alias is "Volume" then set the file_list to every file of this_vol_alias repeat with j from 1 to number of items in file_list (* check to see if a backup script is available *) set this_file to name of item j of file_list if this_file is equal to (backup_script & ".app") then open item j of file_list (* run the backup script *) end if end repeat else display alert "This script can only be executed on volumes" return end if end tell delay 2 (* give some time for the backup script to actually launch *) tell application "Finder" try set bakapp to creator type of process backup_script repeat while bakapp is not equal to "" delay 1 (* the backup is still running, we can check again in a second *) set bakapp to creator type of process backup_script end repeat on error if (ejectable of this_vol_alias is true) then (* display alert POSIX path of dropped_item *) eject this_vol_alias end if end try end tell on error error_message number error_number if the error_number is not -128 then display dialog error_message buttons {"OK"} default button 1 end if end try end open |
Download this script
Now, for the modified backup script. The properties at the top can be modified on a per copy basis to customize the function of the script.
property archive_backup : true property number_of_archives : 3 (* 0 for unlimited *) property with_administrator_privileges : false property one_archive_per_day : true property display_notification : false property backup_target : "Backups/" (* MUST be a folder location with trailing slash! Always relative to home folder *) property rsync_params : "-aEz --delete-excluded" (* END OF PREFERENCES *) set WhereImRunningFrom to path to me tell application "Finder" (* can't run from the script editor *) set AppCreator to creator type of WhereImRunningFrom if AppCreator is "ToyS" then activate of me beep display alert "This script cannot run directly from ScriptEditor" return end if (* NEVER run from the hard drive! *) set bootVolume to name of disk of home (* safety feature! *) set NameOfDisk to name of disk of WhereImRunningFrom if NameOfDisk is bootVolume then beep display alert "Should not run this script from the boot volume!" return end if (* setup backup dir *) set homeDir to path to home folder from user domain set backup_folder to POSIX path of homeDir & backup_target try (* quick and dirty check to see if folder exists - must be a good way to do this in applescript? *) do shell script "cd " & backup_folder on error try do shell script "mkdir " & backup_folder on error display alert "There was an error creating the backup folder " & backup_folder return end try end try (* find source and target *) set backupBase to NameOfDisk & "-Backup" set targetDir to backup_folder & quoted form of backupBase set sourceDir to quoted form of ("/Volumes/" & NameOfDisk & "/") (* set up archive filename *) if archive_backup then set thedate to current date set theday to day of thedate set themonth to month of thedate set theyear to year of thedate set thetime to time of thedate set thedate to "-" & theyear & "-" & shortMonth(themonth) of me & "-" & theday as string if not one_archive_per_day then set thedate to thedate & "-" & thetime as string set backupFolder to quoted form of (backup_folder & backupBase & thedate & "/") end if end tell (* do the backup *) (* try *) if with_administrator_privileges then set excluded to " " else set excluded to " --exclude='.Trash*' --exclude='.Spotlight*' " end if if archive_backup then set posixDir to POSIX file backup_folder set fileList to list folder posixDir set archiveList to {} tell application "Finder" (* Search for existing backups *) repeat with i from 1 to number of items in fileList set thisFile to item i of fileList set filePath to path to resource thisFile in bundle posixDir if thisFile starts with backupBase then set archiveList to archiveList & POSIX path of filePath end if end repeat end tell (* List existing backups in order of last modified date *) set latestArchive to "" set linkDest to "" set listString to "" repeat with x from 1 to number of items in archiveList set listString to listString & " " & quoted form of item x of archiveList end repeat set newString to do shell script "ls -dt " & listString (* sort files by modified date *) set theList to (paragraphs of newString) (* Clear out outdated backups *) if (number of items in theList is greater than number_of_archives) and (number_of_archives is greater than 0) then repeat with y from (number_of_archives + 1) to (number of items in theList) do shell script "rm -Rf " & quoted form of item y of theList end repeat end if if number of items in theList is greater than 0 then set latestArchive to quoted form of item 1 of theList if latestArchive is equal to backupFolder then (* Preserve same target folder *) if number of items in theList is greater than 1 then set latestArchive to quoted form of item 2 of theList else set latestArchive to "" end if end if end if if latestArchive is not equal to "" then set linkDest to " --link-dest=" & latestArchive end if set theScript to "rsync " & rsync_params & linkDest & excluded & sourceDir & " " & backupFolder & "; touch " & backupFolder else set theScript to "rsync " & rsync_params & excluded & sourceDir & " " & targetDir & "; touch " & targetDir end if if with_administrator_privileges then do shell script theScript with administrator privileges else do shell script theScript end if activate of me beep if display_notification then display alert NameOfDisk & " drive backed up" (* on error display alert "There was an error backing up " & NameOfDisk end try *) to shortMonth(themonth) set MonthList to {January, February, March, April, May, June, July, August, September, October, November, December} set mm to 1 repeat until item mm of MonthList = themonth copy mm + 1 to mm end repeat if mm < 10 then copy "0" & mm to mm return mm end shortMonth |
Download this script
Copy the above code in Script Editor, and save it as an Application bundle giving it the name "rsync". If you wish to give it a different name, or maintain a number of copies each with a different name, make sure to modify the first line of the Folder Action script appropriately.
Finally, I can just drop a copy of the rsync application bundle in any thumb drive I want to keep a backup of, and apply the Folder Action to any computer I want to maintain backups on. Since the backup script is using rsync for the backup, I can have multiple backups on any number of computers and they will all mirror the contents of the thumb drive whenever the thumb drive is mounted on them. Additionally, a tar-gzipped copy of the thumb drive can optionally be created with a date stamp for archiving. Deletion of old archives must be managed manually.
If you are having permission issues with some of the files on one of your thumb drives, you can enable the with_administrator_privileges property in the backup script. This will cause the script to ask you for a password every time the thumb drive is mounted before performing the backup, but will perform the backup as an administrator eliminating any permission issues.
I feel that this script can still be improved, but for now it works just fine for my needs. If you have any suggestions for improving this process, feel free to add them in the comments.
1. Comment by Matt
on 26 Feb 2008 @ 11:27 am
I’ve noticed that sometimes the script on my USB stick does not run. I’m not sure why this would be as at other times it runs without any problems – It all seems completely random. Is this a known problem with this script or applescripts in general?
2. Comment by Constantinos
on 26 Feb 2008 @ 1:51 pm
The script has a known problem under Leopard. The problem lies with the line
set the file_list to every file of item i of volume_list, which returns an empty list in Leopard (I don’t know why). It could be fixed by switching to a terminal command, but I haven’t had time to do it yet.3. Comment by lemonteh
on 4 Mar 2008 @ 2:45 am
I was reading through this applescript. If archive backup is turned on, the oldest archive will be deleted when the number of archive reaches the maximum. What happen to the hardlinks then since all the unchanged files are actually hard linked to the previous?
4. Comment by Constantinos
on 4 Mar 2008 @ 2:54 am
[quote post=”85″]What happen to the hardlinks then since all the unchanged files are actually hard linked to the previous?[/quote]
When you delete a file in unix, the file isn’t actually deleted. What is deleted is the link to that file, which usually marks the space on disk as free.
In the case of hard links, what you have is several entries in the disk’s index that point to the exact same position on the disk. As far as the system is concerned those are separate files that reside in the same memory location. When you delete one of them, the relevant index is removed, but the rest of the indexes remain. The file isn’t actually ‘erased’ (or the space it occupies isn’t marked as free) until ALL the hard links pointing to it are removed from the index.
5. Comment by lemonteh
on 6 Mar 2008 @ 4:03 am
Cool! Thanks.
6. Comment by Michael
on 9 Mar 2008 @ 2:33 am
[quote comment=”2237″]The script has a known problem under Leopard. The problem lies with the line
set the file_list to every file of item i of volume_list, which returns an empty list in Leopard (I don’t know why). It could be fixed by switching to a terminal command, but I haven’t had time to do it yet.[/quote]Thanks for the effort thus far, Constantinos.
7. Comment by noxlady
on 10 Mar 2008 @ 3:12 am
Has anybody had a chance to work out the Leopard bug yet? I”m a teacher, and I keep my grades on a thumb drive, so losing them would be disastrous. The old auto backup script made me feel much safer — I’m eagerly awaiting a Leopard update 🙂
8. Comment by Constantinos
on 10 Mar 2008 @ 10:34 am
[quote post=”85″]Has anybody had a chance to work out the Leopard bug yet? Iâ€m a teacher, and I keep my grades on a thumb drive, so losing them would be disastrous. The old auto backup script made me feel much safer — I’m eagerly awaiting a Leopard update :)[/quote]
Since there are people who are actively using this script (I stopped because I’m done working with my memory stick so there’s nothing for me to back up), I’ve sorta fixed the problem. The new version of the folder action (which is the only thing that changed) seems to work just fine with Leopard, and should also just work with Tiger. I’m saying ‘sorta’ fixed the problem because it’s not a real Applescript solution, it’s piping terminal commands to search for the file, a technique I used for simulating encrypted thumb drives in OS X and appears to work without issues, but it’s not my favourite solution in the world.
Let me know how it works out. Again, only the folder action changed, which is what actually launches the backup script. The script itself is unchanged, so if it launches automatically it should just work the same way it did before.
9. Comment by Constantinos
on 10 Mar 2008 @ 10:36 am
Oh yeah, forgot to mention: The modification means that you can no longer have a list of differently named backup scripts, which will launch depending on what thumbdrive you insert. All the thumbdrives you use need to have their backup script named the same. I’m guessing it’s not a real problem for anyone using this, but just a heads up anyway.
10. Comment by noxlady
on 17 Mar 2008 @ 6:43 am
Hey, it works! Well, my rsync script launches, anyhow:) I’m pretty sure that once rsync launches I’m home free, it was just those darn folder actions that were the problem. Thanks so much for the fix!!!!
11. Comment by Mark
on 23 Mar 2008 @ 12:39 pm
[quote comment=”2066″]Is there a way to do this in reverse?
i.e. So that when I mount my flash drive it executes an automatic backup of a specific folder or specific folders from my hard drive onto the flash drive?[/quote]
Here is a link to a tutorial on how to do this: http://maclawstudents.com/blog/techniques/automatic-backups-to-usb-flash-drives/
It basically uses all Constantinos’ code but makes a backup _to_ your flash drive. It suffers from the same Leopard folder-action bug. But it works perfectly in Tiger.
12. Comment by Kevin
on 21 Jun 2008 @ 10:18 pm
First, thanks for such a great utility.
I am using Leopard, and am wondering if I am doing something wrong. I have a Backups folder that was created and the backup appears to have worked. But instead of using rsync to do incremental copies, it seems to just create an entire folder with the date appended.
Thus, if I have an almost full 2GB flash drive, every day I plug it this script uses almost 2GB per day.
Am I wrong in expecting it to just create one folder and incrementally back it up? Does anyone know how I could modify the rsync command to do this?
13. Comment by Constantinos
on 21 Jun 2008 @ 10:24 pm
[quote post=”85″]I am using Leopard, and am wondering if I am doing something wrong. I have a Backups folder that was created and the backup appears to have worked. But instead of using rsync to do incremental copies, it seems to just create an entire folder with the date appended.
Thus, if I have an almost full 2GB flash drive, every day I plug it this script uses almost 2GB per day.[/quote]
That’s how rsync works. It copies everything using hard links. Therefore even though it looks like you have 5 different copies of all of your files, in fact you only have one copy that is pointed to from 5 different memory locations.
Try this: Go in your backups folder, click on one specific backup, and hit cmd-I to see it’s info. This will tell you the total size of that folder, which should be around 2gb (as it’s a whole copy of your memory stick). Now go one level up, to the Backups folder, and do the same. You’ll notice that the ENTIRE Backups folder, which contains all 5 backup copies of your memory stick, is in fact just over 2Gb and NOT 10Gb in size.
The ‘incremental’ aspect of the backup is automatically handled by rsync, where if a file hasn’t changed since the last copy, instead of copying it over it just creates a hard link to the copy saved by the previous backup.. 🙂
14. Comment by Kevin
on 22 Jun 2008 @ 12:41 pm
I did a cmd-i on the individual folders, not on the Backups folder. Thanks for clearing that all up!
15. Comment by Jacob
on 17 Jul 2008 @ 5:15 pm
I’m getting an error message: “Finder got an error: Can’t get original item of doc file “File name” of disk “Diskname”
Anyone else seen this? Have a solution?
The backup and eject script seems to work OK — this is only on the auto-backup when mounted script.
16. Comment by Andy
on 20 Aug 2008 @ 3:04 am
This seems like a really cool utility and I’d love to figure out how to make it work. I’m fairly new to Macs and while I’ve tried to follow the instructions carefully I just can’t seem to figure out how to make it work. I’m so lost that I’m not even sure where the files should end up (after being backed up). It also seems like I need to save a file on the flash drive but again, I’m not sure which file.
I know I’m really a novice on this so feel free to ignore me – I’d understand. But man I’d love to get this working. I’m on Leopard by the way.
Thanks!
17. Comment by Constantinos
on 20 Aug 2008 @ 11:35 am
[quote post=”85″]I just can’t seem to figure out how to make it work. I’m so lost that I’m not even sure where the files should end up (after being backed up). It also seems like I need to save a file on the flash drive but again, I’m not sure which file.[/quote]
You’re probably right in that I could’ve made the explanation for this a bit simpler.
You only really need two of the three, above scripts to make this work. The first script on this page (
auto_backup.scpt), you need to download as-is and save it as a folder action as per the instructions right under it. The last script on this page (rsync.app) you need to download, extract (as the download is compressed), and simply move the extracted file on to the thumb drive you wish to have backed up.Those are the two files you need. To modify the options for the backup, you need to open up Script Editor (found under Applications / Utilities), open the
rsync.appfile with it, modify the settings found at the beginning of the file, and save it.Hope this helps you!
18. Comment by Xavier
on 23 Aug 2009 @ 11:41 pm
The following how to might let do what you want in a simple way. If you know what you want to back up and where, you just plug, wait till it does the job, and unplug the key.
http://mogrifiers.blogspot.com/2009/08/quick-usb-backup-from-mac.html
19. Comment by Talcorath
on 1 Sep 2010 @ 11:56 pm
Does this script and folder action work under Snow Leopard? I’ve been looking for a free solution and yours looks the most valid, just not sure if it still works.
20. Comment by Guapo
on 4 Dec 2010 @ 4:44 am
I second what Talcorath said above. I like the idea of what you’re trying to do, but I don’t know enough about AppleScript to know if all this will work under Snow Leopard.
I got stuck a the part where you said to launch the Folder Actions Setup utility. This doesn’t seem to be anywhere on my Mac. I know I haven’t deleted it as this is a new MBP (purchased Oct 2010). Please help.
21. Comment by Constantinos
on 30 Dec 2010 @ 8:54 am
[quote comment=”21340″]I got stuck a the part where you said to launch the Folder Actions Setup utility. This doesn’t seem to be anywhere on my Mac. I know I haven’t deleted it as this is a new MBP (purchased Oct 2010). Please help[/quote]
In Snow Leopard, right click on the /Volumes/ folder. If you don’t see a Folder Actions entry in the contextual menu, look for a Services entry at the end – Folder Actions should be in there.
22. Comment by El Guapo
on 18 Jan 2011 @ 9:21 pm
[quote comment=”2329″][quote post=”85″]I am using Leopard, and am wondering if I am doing something wrong. I have a Backups folder that was created and the backup appears to have worked. But instead of using rsync to do incremental copies, it seems to just create an entire folder with the date appended.
Thus, if I have an almost full 2GB flash drive, every day I plug it this script uses almost 2GB per day.[/quote]
That’s how rsync works. It copies everything using hard links. Therefore even though it looks like you have 5 different copies of all of your files, in fact you only have one copy that is pointed to from 5 different memory locations.
Try this: Go in your backups folder, click on one specific backup, and hit cmd-I to see it’s info. This will tell you the total size of that folder, which should be around 2gb (as it’s a whole copy of your memory stick). Now go one level up, to the Backups folder, and do the same. You’ll notice that the ENTIRE Backups folder, which contains all 5 backup copies of your memory stick, is in fact just over 2Gb and NOT 10Gb in size.
The ‘incremental’ aspect of the backup is automatically handled by rsync, where if a file hasn’t changed since the last copy, instead of copying it over it just creates a hard link to the copy saved by the previous backup.. :)[/quote]
23. Comment by Guapo
on 19 Jan 2011 @ 2:57 am
[quote post=”85″]Try this: Go in your backups folder, click on one specific backup, and hit cmd-I to see it’s info. This will tell you the total size of that folder, which should be around 2gb (as it’s a whole copy of your memory stick). Now go one level up, to the Backups folder, and do the same. You’ll notice that the ENTIRE Backups folder, which contains all 5 backup copies of your memory stick, is in fact just over 2Gb and NOT 10Gb in size.[/quote]
Mine’s not working like that. I get the total of all folders when I go up one level.
24. Comment by Guapo
on 21 Jan 2011 @ 3:23 am
[quote post=”85″]Mine’s not working like that. I get the total of all folders when I go up one level.[/quote]
Could it be that I need to change some of the preferences/properties of the rsync.app? Referring to my concern above.
25. Comment by Nichole
on 12 Jun 2011 @ 11:58 pm
Where do I go to access my backedup files?
26. Comment by Constantinos
on 13 Jun 2011 @ 7:41 pm
[quote comment=”32730″]Where do I go to access my backedup files?[/quote]
The 6th property in the actual backup script reads
property backup_target : "Backups/" (* MUST be a folder location with trailing slash! Always relative to home folder *)
If you did not change it, then your backups would be in ~/Backups/, where ~/ is your Home directory. So Open up the finder, click on your home dir, and look for a folder called Backups.
27. Comment by Nichole
on 20 Jun 2011 @ 7:57 am
[quote comment=”32771″][quote comment=”32730″]Where do I go to access my backedup files?[/quote]
The 6th property in the actual backup script reads
property backup_target : "Backups/" (* MUST be a folder location with trailing slash! Always relative to home folder *)
If you did not change it, then your backups would be in ~/Backups/, where ~/ is your Home directory. So Open up the finder, click on your home dir, and look for a folder called Backups.[/quote]
Thank you for your reply… I went to finder, searched for backups and nothing comes up. I followed the instructions as per above, and my flashdrive seems to get to business as soon as its mounted. Also, when I save something the screen briefly flashes (as if it’s backing up – just my imagination?)
I’m having a heck of a time with this… Nothing seems to be saved anywhere on my computer. I def. did not change the script. Any help would be greatly appreciated. I recently lost everything on a different flash drive and don’t want to go through that again.
28. Comment by skororu
on 26 Nov 2013 @ 4:30 am
Update for OSX Mavericks
I made a quick hack to the folder action script that attaches to the /Volumes directory so it works for OSX Mavericks. The script that sits on the memory stick itself works fine without any modification.
http://pastebin.com/d77rwsrP