topic Re: List the latest file in Operating System - OpenVMS

List the latest file

Per Arvidsson — Fri, 08 May 2009 05:37:36 GMT

In DCL how can I get the latest created file on a directory?

Re: List the latest file

Joseph Huber_1 — Fri, 08 May 2009 05:59:56 GMT

You can write a DCL command file:

lastfile=""
last="17-NOV-1858"
last=f$cvtim(last,"COMPARISON")

Loop with file=f$search("*.*") over the directory,
get the creation date cdt=f$file(file,"CDT")
convert the date to comparison cdt=f$cvtim(cdt,"COMPARISON")
Compare to the last time saved
Set last to cdt if cdt .ges. last
Set lastfile to file in this case
Continue loop.

Or search on the VMS freeware disks for the program DIRBYDATE: it does not give You just the latest, but a directory listing with the latest first or last in the list.

Re: List the latest file

Hakan Zanderau ( Anders — Fri, 08 May 2009 06:08:36 GMT

Per,

What are you trying to do ?
We need more detailed information.

Hakan

Ps. Jobbade tidigare pÃ¥ VMS-supporten hos Digital/Compaq/HP. Ds.

Re: List the latest file

Kris Clippeleyr — Fri, 08 May 2009 06:48:54 GMT

Per,

You could use QDSB, downloadable from
http://www.quadratrix.be/qdsb.html

Example:
$ QDSB/SORTED=DATE_C=ORDER=DESC

Kris (aka Qkcl)

Re: List the latest file

Per Arvidsson — Fri, 08 May 2009 07:35:42 GMT

Thank you all, Wow!
What a response

Re: List the latest file

Per Arvidsson — Fri, 08 May 2009 07:43:30 GMT

I tried to pipe dir and sort but didnt succeed. These answers will do

Re: List the latest file

Joseph Huber_1 — Fri, 08 May 2009 07:59:39 GMT

I think Kris's program is the most excellent doing a sorted directory anyway.

>> tried to pipe dir and sort but didnt succeed.

Because the default date format is not ISO or VMS "comparison": one has to switch date-format before the directory command, and has to fix the output fields with the /width qualifier, then one can pipe the output through sort.

I did this for the file size (because it's simpler :-), see
http://wwwvms.mppmu.mpg.de/util_root/com/dir_by_size.com

Re: List the latest file

Joseph Huber_1 — Fri, 08 May 2009 08:44:46 GMT

A quick hack in DCL piping directory output into sort is at
http://wwwvms.mppmu.mpg.de/util_root/com/dir_by_date.com

but it will break the correct order and display whenever a dir-/file-specification exceeds the filename field width (80 in my example).

A slower DCL version using f$search loop is
http://wwwvms.mppmu.mpg.de/util_root/com/dir_by_date2.com

Re: List the latest file

Hakan Zanderau ( Anders — Fri, 08 May 2009 08:47:57 GMT

$ DEFINE/EXEC/TAB=LNM$DT_FORMAT_TABLE LIB$DATE_FORMAT_COMPARISON "!Y4-!MN0-!D0"
$ DEFINE LIB$DT_FORMAT LIB$DATE_FORMAT_COMPARISON,LIB_TIME_FORMAT_001
$ pipe (dir/date/wid=file=40 | search sys$input ";" | sort/key=(pos:43,siz:22,desc) s
ys$input sys$output)

Hakan

Re: List the latest file

Joseph Huber_1 — Fri, 08 May 2009 10:19:03 GMT

BTW, the LIB$DT_FORMAT feature only works if
@sys$startup:lib$dt_startup has been executed (best insert this in systartup_vms ).

Re: List the latest file

Hakan Zanderau ( Anders — Fri, 08 May 2009 11:01:58 GMT

Joseph,

The default date & time formats

LIB$DATE_FORMAT_001
LIB$TIME_FORMAT_001

are defined in SYS$STARTUP:VMS$INITIAL-050_LIB.COM

You can define your own date and time format
in table lnm$dt_format_table and make use of it without running LIB$DT_STARTUP.COM

I think I'm right about this, but I'm not 100% sure.

Hakan

Re: List the latest file

Joseph Huber_1 — Fri, 08 May 2009 11:30:34 GMT

As far I tested, only privileged users can do it.
So for average users it is better to rely on definitions done from systartup_vms.

Re: List the latest file

Hakan Zanderau ( Anders — Fri, 08 May 2009 12:27:41 GMT

Joseph,

Oppps....forgot about the privileges needed to
define names in lnm$dt_format_table.

The truth is that I have never worked without
privileges on VMS........ and have all privileges enabled by default.

I know...., but that's the way it is ;-)

Hakan

Re: List the latest file

Steven Schweda — Fri, 08 May 2009 15:05:26 GMT

> You can write a DCL command file:

You're right. This came up in the Linux
forum:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1335784

After saying that it would be easy in DCL, I
figured that I ought to try it.

$! 8 May 2009. SMS.
$!
$! Find newest file in (wildcard) P1 specification.
$!
$ prev_file_spec = ""
$ date_max_c = f$cvtime( "17-NOV-1858 00:00:00.00", "COMPARISON")
$ file_spec_max = ""
$!
$ loop_top:
$!
$ file_spec = f$search( p1)
$!
$! Quit if out of files, or (non-wildcard) look-up repeats.
$!
$ if ((file_spec .eqs. "") .or. -
(file_spec .eqs. prev_file_spec)) then goto loop_end
$!
$ prev_file_spec = file_spec
$!
$! Get file revision date, and convert it to "COMPARISON" format.
$!
$ file_date = f$file_attributes( file_spec, "RDT")
$ file_date_c = f$cvtime( file_date, "COMPARISON")
$!
$! Save the information for a new newest file.
$!
$ if (file_date_c .gts. date_max_c)
$ then
$ file_spec_max = file_spec
$ date_max_c = file_date_c
$ endif
$!
$ goto loop_top
$ loop_end:
$!
$! If anything was found, display its information.
$!
$ if (file_spec_max .nes. "")
$ then
$ write sys$output file_spec_max
$ write sys$output date_max_c
$ endif
$!

Easy enough, I reckon.

Re: List the latest file

Joseph Huber_1 — Fri, 08 May 2009 17:10:45 GMT

And here (without own programming), let the fine GNV do the work:-)

$ bash -c "ls -lt"

Re: List the latest file

Steven Schweda — Fri, 08 May 2009 17:40:40 GMT

> $ bash -c "ls -lt"

That gives me more than "the [...] file".
Or did you mean this?:

$ bash -c "ls -lt | head -2 | tail -1"

The DCL method runs faster, and easily does
recursive descent into subdirectories
("[...]"), which is tougher to do with a
UNIX-like method.

As usual, many things are possible.

Re: List the latest file

Joseph Huber_1 — Fri, 08 May 2009 18:31:54 GMT

>>That gives me more than "the [...] file".
>>Or did you mean this?:
>>$ bash -c "ls -lt | head -2 | tail -1"

Yea right, thats exactly to get the one newest file, as Your DCL command file is doing.

I was just comparing the bash one liner to my dir_by_date.com .