birthtime_touch is a simple command line tool that works similar to touch, but changes a file's creation time (its "birth time") instead of its access and modification times.
Usage:
birthtime_touch --adjust (+|-)hhmmss file1 [file2 ...]
The following example adds 7 hours to the creation time of aFile:
birthtime_touch --adjust +070000 aFile
birthtime_touch currently only runs on Mac OS X. The minimum required version is Mac OS X 10.6. birthtime_touch is known to work for files that are stored on HFS+ and MS-DOS filesystems.
The main problem why birthtime_touch does not work on all systems and for all filesystems, is that not all filesystems store a file's creation time, and for those that actually do store the creation time there is no standardized API to access/change that information.
birthtime_touch currently does not handle symbolic links correctly.
Generally birthtime_touch should adopt those features from touch for which it makes sense. Notably these are:
- Set creation time to the same time as a reference file
- Set creation time to a specifed time
- Extend
--adjustso that days can be specified - Prevent dereferencing of symbolic links
In addition the following things would also be nice:
- Support short command line options
- Provide a man page
- Run not only on Mac OS X, but also on Linux and Windows
The following filesystems are known to store file creation time, so supporting them in the future is at least a possibility.
- ext4
- Btrfs
- ZFS
- JFS
- UFS2
- NTFS. The open source filesystem driver
ntfs-3gexposes creation time via extended file attributes. - Samba
Install Xcode, then run
./build.sh
You can find all build results in the build subfolder. Because birthtime_touch is such a simple program, I didn't take the time to set up a proper Xcode project.
The current implementation of birthtime_touch is based on this StackOverflow answer: It uses the Cocoa class NSFileManager for changing the file creation time. Here is an alternative SO answer that shows how to achieve the same result with the Core Foundation function CFURLSetResourcePropertyForKey.
Other useful references that concern themselves with file creation time:
- http://unix.stackexchange.com/questions/7562/what-file-systems-on-linux-store-the-creation-time
- https://lwn.net/Articles/397442/
- http://unix.stackexchange.com/questions/91197/how-to-find-creation-date-of-file
- http://superuser.com/questions/387042/how-to-check-all-timestamps-of-a-file
birthtime_touch is licensed under the GNU General Public License (GPLv3). See the file COPYING.
The motivation for writing birthtime_touch was to fix the creation time of image files after they are imported from a digital camera that had its time zone set up wrongly at the time when the images were shot. Here are the three commands that are necessary to add 7 hours to a single image file:
birthtime_touch --adjust +070000 anImage.jpg
touch -A +070000 anImage.jpg
exiv2 --keep --adjust +07 ad anImage.jpg
The Exiv2 utility is necessary to fix the image file's Exif metadata. After these changes, the image file probably must be re-imported into the digital image library program (e.g. iPhoto).