Re: What is the difference between Change time and Modify time?
On Sat, Jul 30, 2011 at 2:10 PM, Theodore Kilgore kilg...@banach.math.auburn.edu wrote: The question in the header refers, of course, to the options found under Sort Order. Frankly, I can not tell the difference between the meanings of these two options -- unless perhaps I would take a deep dive into the source code. The man page does not seem to provide enlightenment on this point, either. Basically, Modify Time is when the contents of the file have been changed, and Change Time is when anything has been done to the file (copied/moved/renamed/changed permissions/etc) Modify time is basically the timestamp of the file, which can be artificial (for example, by using the touch command), but change time (if filesystem supports it) shows the actual timestamp when the file was last changed (which includes changing the contents, as well as file being written/copied/moved/renamed/chmod etc). For example, sort a directory by Change Time. Now, rename a file. It should be moved to the bottom of the list (because it has been changed). The Modify Time won't change because you didn't touch the contents of the file. Modifiy Time is usually the common timestamp, that is shown in directory listings and in the MC default panel configuration. So for example if you unzip a file, the modified time will be set to the timestamp that was saved in the archive, but the change time will be the time that you unzipped the file. The stat command will show you the various times on record for a file. The touch command lets you set them to different values. ___ mc mailing list http://mail.gnome.org/mailman/listinfo/mc
Re: What is the difference between Change time and Modify time?
On Sat, 30 Jul 2011 14:10:41 -0500 (CDT) Theodore Kilgore wrote: To answer your question, please read the stat(2) man page and find description of change time (ctime) and modify time (mtime) Probably, the built-in help should be more verbose about sort orders. -- Andrew ___ mc mailing list http://mail.gnome.org/mailman/listinfo/mc
Re: What is the difference between Change time and Modify time?
On Sun, 31 Jul 2011, Andrew Borodin wrote: On Sat, 30 Jul 2011 14:10:41 -0500 (CDT) Theodore Kilgore wrote: To answer your question, please read the stat(2) man page and find description of change time (ctime) and modify time (mtime) Probably, the built-in help should be more verbose about sort orders. No joke. As to your advice to look up stat yes it does seem to help, but it still leaves questions about consistent behavior, or the lack thereof, which I will describe in more detail below. First, here is what the man page says: The field st_mtime is changed by file modifications, for example, by mknod(2), truncate(2), utime(2) and write(2) (of more than zero bytes). Moreover, st_mtime of a directory is changed by the creation or dele- tion of files in that directory. The st_mtime field is not changed for changes in owner, group, hard link count, or mode. The field st_ctime is changed by writing or by setting inode informa- tion (i.e., owner, group, link count, mode, etc.). The above says clearly that the mtime data is changed by the creation of deletion of files whereas nothing is said about that under ctime. Presumably, applying basic logic, the ctime would of course also need to be changed (i. e. applied in the first place) if the file is a brand new one which previously did not exist, and therefore it might have approximately the same effect to sort by ctime under those circumstances as to sort by mtime. Now, here is what is very funny: Connecting to an ftp site (ftp.osuosl.org, for example), one might wish to look for the new files in a certain directory. To do that, the sensible thing is to arrange the files by date of creation. When I tried to do this recently from a certain netbook, the mtime option produced absolutely no visible effect on the file listing, but the ctime option did what was intended, instead. I do have to amend something I said yesterday, though. My mistake and I apologize. It was not on the ARM netbook that the funny behavior occurred. It was on an ASUS eeePC (Intel architecture, and running Slackware-current). The intent was to keep current with Slackware-current, obviously. On my regular-sized machines, I have always used the mtime option previously on simmilar occasions, with no problems, but here it did not work, as I said. The only other difference was that my partitions on the eeePC are all mounted with the option noatime in order to save on writes to the SSD devices inside it. But atime and ctime are not the same thing, are they? And furthermore one would expect that to mount physical partitions noatime would have no influence at all upon the way that virtual filesystems get mounted. For the above reasons, I am still a bit puzzled about what happened, but thanks for the information about where to look all this stuff up. The explanation in the stat man page is quite clear. Of course, I could try to reproduce the problem. But for all we know the problem might have been a bug in a previous version of MC which was on the eeePC prior to the upgrade, or some other package which was causing the screwy behavior. So if on testing the problem is not repeatable I guess we would never know what caused it. :-/ Theodore Kilgore ___ mc mailing list http://mail.gnome.org/mailman/listinfo/mc
What is the difference between Change time and Modify time?
The question in the header refers, of course, to the options found under Sort Order. Frankly, I can not tell the difference between the meanings of these two options -- unless perhaps I would take a deep dive into the source code. The man page does not seem to provide enlightenment on this point, either. I have found out that the two options can sometimes act slightly differently, perhaps depending on distro or hardware, or something even more mysterious. The usual occasion on which I would wish to sort files by date instead of by name occurs when I would connect to some repository and I want to get the most recent files in a certain directory. I have always used modify time to do the sorting, and it worked perfectly. But recently I tried to do this using an ARM netbook. The modify time then produced no change in the listing order of the files at all. But when I tried change time instead, I got the desired results. Now, as well as being built on ARM architecture, the netbook is also running a different distro from the rest of my machines. Thus, the important factor might possibly be the configuration of the distro, or it could be due to some quirk of the ARM architecture. However, I still can not tell what the difference between Modify time and Change time was supposed to be in the first place, nor, for that matter, why both of these are separately listed as options when their names seem to mean the same thing with synonymous words. It seems to me to be something which is either redundant or confusing, or possibly both. Therefore, I thought it might be good to ask. Theodore Kilgore ___ mc mailing list http://mail.gnome.org/mailman/listinfo/mc
