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touch(1) can only change modification and access times, but has no options for creation time. This does not work, at least not on Lion.

So how do I change the creation time, also referred to as birthtime in fstat(2)? There's no corresponding call in utimes(2) and there doesn't seem to be any command line tool for this.

I know I can copy the file to a new file, which then gets the current time as birthtime (and then delete the original), but surely there must be a better way?

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  • 1
    touch -t yyyymmddhhmm $file does seem to change the creation date, but only if it's before the original creation date.
    – Lri
    Commented Apr 20, 2012 at 5:22
  • Good point, @Lri - that actually makes sense, since that updates the mtime and atime and a file couldn't be accessed or modified before it was created. But it doesn't let me set a newer creation time.
    – Ingmar Hupp
    Commented Apr 20, 2012 at 13:32
  • Are you referring to changing it via the command line, or just in general, not necessarily with the CLI?
    – daviesgeek
    Commented Jun 29, 2012 at 21:36
  • Frankly I would hope you can't change it, as surely it would defeat the entire point of the field?! Also I suspect some of hte problem is that birthtime/creation time isn't a standard filesystem feature; hfs added it in their extended attributes, I think - so unless utilities have been updated to recognise that, they won't be able to do much with it.
    – Caesium
    Commented Aug 2, 2012 at 13:59

2 Answers 2

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touch -t also changes the creation time if the target modification time is before the original creation time.

SetFile can set the creation time to be before the modification time or in the future.

-d date    Sets the creation date, where date is a string of the
           form: "mm/dd/[yy]yy [hh:mm:[:ss] [AM | PM]]" Notes:
           Enclose the string in quotation marks if it contains spa-
           ces. The date must be in the Unix epoch, that is, between
           1/1/1970 and 1/18/2038. If the year is provided as a two-
           digit year, it is assumed to be in the 21st century and
           must be from 00 (2000) through 38 (2038).

This would set the creation time to the modification time:

SetFile -d "$(GetFileInfo -m test.txt)" test.txt

SetFile and GetFileInfo are part of the command line tools package, which can be downloaded from Xcode's preferences or developer.apple.com/downloads.

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  • Strictly speaking "birthtime" (crtime) and ctime are different things (see File creation times in ZFS
    – G. Cito
    Commented May 7, 2015 at 18:23
  • Of course access and modification times are often the same - but for different reasons. The touch and stat manual pages have the details. I'd be interested to know how OpenZFS for OSX as well as the OSX "native" filesystems handle crtime field or what stat reports for the crtime on various versions of OSX.
    – G. Cito
    Commented May 7, 2015 at 18:27
-1

Try:

cat filename > newfile
mv filename ~/.Trash/
mv newfile filename

That should work.

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    You'll still need to delete the original. Ingmar had already covered this.
    – Hippo
    Commented Apr 20, 2012 at 1:53
  • Whoops, should've read better. But no, there is not a better way...
    – Sean Freitag
    Commented Apr 20, 2012 at 3:22

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