UNIX for Beginners Questions & Answers

I doubt that this will work on Ubuntu systems either, but it might be worth a try. The operating system I'm using doesn't have the debugfs or findmnt utilities and the date utility doesn't have a -d option, but the following code seems to do what I think you're trying to do.

Code:

crtime-at() {
	stat -t '%Y-%m-%d %H:%M:%S' -f '%SB%t%N%n' * | sort | awk '
		NR > 1 {printf("%s,", last) }
		{	last = $0 }
		END {	print last }'
}

if your shell allows hyphen characters in function names (which is not portable and is not required by the standards) and your system has a BSD based version of the stat utility.

Unfortunately, the stat utility is not specified by the standards either so methods used to print a file's creation time (if the file system the files reside on keeps a file's creation time [which is not required by the standards]) varies from system to system and the methods used to specify strftime()-like format strings for printing dates varies from system to system (with some systems not providing creation dates nor any way to get the date/time format you want).

If nothing else, maybe the above code will show you how to use awk to convert a sorted text file into a single line output with input lines separated by commas instead of <newline>s.

This was tested on macOS Mojave version 10.14.3 with a BSD-based stat utility (probably with macOS extensions). Note that this version just sorts on the YYYY-mm-dd HH:MM:SS date/time stamps instead of trying to get a finer grained timestamp using UNIX Epoch times.

I have no idea what the stat utility man page on your system says about printing file creation dates or about ways to specify the format of dates that are to be printed.

Hey Don!

If you need a Linux server to log into and try commands I have a Linode Ubuntu server I can create an account for you.

Let me know!

Hi Tim,
It's too late tonight (i.e. this morning) for me. I need some sleep.

But, if you e-mail me details on how to login to your Ubuntu system, I'll play around with it later today.

Cheers,
Don

Thanks Don!
I'll also like to try your system out tomorrow.
In the meantime, I will make the changes you suggested.

It's good to have so much help. This is the way to code -

On (plain) Ubuntu systems, you won't get a file's crtime from stat, as its %w "format sequence" supplies 0, or "-", respectively:

Code:

Access: 2019-03-13 11:43:18.362189910 +0100
Modify: 2019-03-09 20:25:05.000000000 +0100
Change: 2019-03-13 11:48:32.571558428 +0100
Birth: -

The debugfs crtime entry might be closer to the desired result, but isn't it strange that it is later than mtime?

Code:

  ctime: 0x5c88e000:88452870 -- Wed Mar 13 11:48:32 2019
  atime: 0x5c88dec6:565a5158 -- Wed Mar 13 11:43:18 2019
  mtime: 0x5c841311:00000000 -- Sat Mar  9 20:25:05 2019
 crtime: 0x5c84136a:ba74cad4 -- Sat Mar  9 20:26:34 2019

You could simply pipe your result list through

Code:

 | paste -sd,

Here is a slightly optimized version of your code that should run a little bit faster and produce the output I think you're trying to get.

Code:

#!/bin/bash
crtime-at() {
	fs=$(findmnt -n -o SOURCE --target "$PWD")
	ls -id * | while read -r inode target
	do
		crtime=$(sudo debugfs -R "stat <$inode>" "${fs}" 2> /dev/null |
		    grep -oP 'crtime.*--\s*\K.*')
		crtime=$(date -d "$crtime" '+%Y-%m-%d %H:%M:%S')
		printf '%s\t%s\n' "$crtime" "$target"
	done | sort | paste -sd,
}
crtime-at
cd /tmp
crtime-at

This was tested on Ubuntu running release 4.15.0-32-generic. Unfortunately, as noted by RudiC on this Ubuntu release, the stat utility only shows - for the birth time (aka struct stat crtime field) of a file and the ls utility has no option to print (or sort) on the creation timestamp of a file even if the underlying file system stores this data. I used the paste as RudiC suggested since it should be more efficient than the awk code I suggested in an earlier post in this thread. I didn't observe the mtime before crtime on any of the files I observed on Ubuntu, but that abnormality certainly could be created with a C or C++ program or using the touch utility.

If you want to switch to using mtime instead of crtime you could just use stat and make your loop much simpler as suggested before by using:

Code:

 stat --printf='%y\t%n\n' * | sort | paste -sd,

If you don't like the sub-seconds and the offset from GMT in the output that produces, those artifacts could very simply be removed if you go back to a slightly modified version of the awk code I suggested instead of using paste.

I moved the check for the filesystem out of the loop since all files in a directory are by definition in the same filesystem. And, we can get the inode numbers and the file names names from ls directly without needing to invoke ls a second time and invoking cut inside the loop to extract it. The two invocations of your function after its definition were used by me to verify the output I was getting. Feel free to replace that code with whatever else you were doing in your script.

If there's anything in this version of your function that you don't understand, ask and I'll try to explain it for you.

I hope this helps.

Just for the fun of it (and be aware that eval comes with its known problems):

Code:

for FN in *; do  eval $(stat -c"sudo debugfs -R 'stat <%i>' \$(grep %m /etc/mtab| cut -d' ' -f1)" $FN) 2>/dev/null | sed -n "/^crtime.*--/{s///;s/$/ $FN/p}" ; done  | paste -sd,

Unfortunately, stat and debugfs aren't mutually compatible, e.g. in the fields that they use and output.