Re: How to find by birth time?

[James Youngman]

On Sun, Nov 20, 2011 at 9:05 PM, Peng Yu <address@hidden> wrote:
>> Yes.  It's explained in the Texinfo documentation for find.
>
> I see the word 'birth' appears in the following two places.

... neither of which is the Texinfo documentation for find, though.
Read that with "info find".

>
>       -newerXY reference
>              Compares the timestamp of the current file with reference.   The
>              reference  argument  is  normally the name of a file (and one of
>              its timestamps is used for the comparison) but it may also be  a
>              string  describing  an  absolute time.  X and Y are placeholders
>              for other letters, and these letters select which time belonging
>              to how reference is used for the comparison.
>
>              a   The access time of the file reference
>              B   The birth time of the file reference
>              c   The inode status change time of reference
>              m   The modification time of the file reference
>              t   reference is interpreted directly as a time
>
>              Some  combinations are invalid; for example, it is invalid for X
>              to be t.  Some combinations are not implemented on all  systems;
>              for example B is not supported on all systems.  If an invalid or
>              unsupported combination  of  XY  is  specified,  a  fatal  error
>              results.   Time  specifications are interpreted as for the argu-
>              ment to the -d option of GNU date.  If you try to use the  birth
>              time  of  a  reference file, and the birth time cannot be deter-
>              mined, a fatal error message results.  If  you  specify  a  test
>              which  refers  to  the  birth time of files being examined, this
>              test will fail for any files where the birth time is unknown.
>
>
>     All the single character options except -H and -L as well as -amin,
>     -anewer, -cmin, -cnewer, -delete, -empty, -fstype, -iname, -inum,
>     -iregex, -ls, -maxdepth, -mindepth, -mmin, -path, -print0, -regex and all
>     of the -B* birthtime related primaries are extensions to IEEE Std
>     1003.1-2001 (``POSIX.1'').

This also is not from the GNU find documentation (any version, as far
as I can tell).

>
>
> Since it say "-B* birthtime ...", I guess that these are related to
> birth time. But none of the following item explicitly says "birth". It
> seems to me that "file's inode creation" is the same as "birth". If
> so, I think that the info should be more explicit about this, as birth
> time have been used in other places like man stat.
>
> Also, how come 'man find' even doesn't mention -Btime?

Because GNU find does not implement that predicate.

>
>
>     -Bmin n
>             True if the difference between the time of a file's inode cre-
>             ation and the time find was started, rounded up to the next full
>             minute, is n minutes.
>
>     -Bnewer file
>             Same as -newerBm.
>
>     -Btime n[smhdw]
>             If no units are specified, this primary evaluates to true if the
>             difference between the time of a file's inode creation and the
>             time find was started, rounded up to the next full 24-hour
>             period, is n 24-hour periods.
>
>             If units are specified, this primary evaluates to true if the
>             difference between the time of a file's inode creation and the
>             time find was started is exactly n units.  Please refer to the
>             -atime primary description for information on supported time
>             units.
>
>
> BTW, I'm not sure the version of the info and man page of find. But I
> have the following version of find.
>
> ~$  find --version
> find (GNU findutils) 4.4.2

This is indeed GNU find, but you're not reading the matching
documentation.   Perhaps you're not looking in the right place ("info
find").

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