On 11/28/05, Wijaya Edward <[EMAIL PROTECTED]> wrote: > > > > ----- Original Message ----- > From: Jennifer Garner <[EMAIL PROTECTED]> > Date: Monday, November 28, 2005 12:30 pm > Subject: how to get file's creation time > > > > How to get file's creation time,NOT last modify time?Thanks. > > I don't think it is possible, in unix environment. > > Read this comment by Randall Schwartz, > http://www.perlmonks.org/index.pl?node_id=479799 > > Hope it gives you a hint ... > > --- > Regards, > Edward WIJAYA > SINGAPORE
It depends on what you mean by "creation". stat() on POSIXish systems returns ctime, which is the inode creation time, which is the time the physical location on disk was first written to (actually, these days it's the time the vnode was fist written to, but you don't really care that much about disk geometry, do you?). The time will not be preserved across relocations (i.e. mv and cp will destroy it), although many archivers reinstate the file's original ctime when files are restored from backup. For most applications, though, "when this particular disk space was reserved for data" is an effective synonym for "when this file was created. When you start moving files around, the questions merlyn raises become much more important. For the record, Kirk McKusick--one of the original implemetors of UFS/FFS and the creator of UFS2--tells the story a little differently. According to him, the FFS originally intended to use ctime as the creation time, but they discovered that dump needed a record of inode creation to make incrimental backups effectively. In fact, UFS2 includes a btime (call it "birth time" if you want) field that is stable across inode relocations when the system uses btime aware file system operations. I don't know, though, if the Perl team has plans to update stat() to support it on systems where it is available. Of course, that isn't completely at odds with merlyn's comments: the original unix developers started implementing file systems a decade before Berkely started work on FFS. HTH, -- jay -------------------------------------------------- This email and attachment(s): [ ] blogable; [ x ] ask first; [ ] private and confidential daggerquill [at] gmail [dot] com http://www.tuaw.com http://www.dpguru.com http://www.engatiki.org values of β will give rise to dom!
