This is a text-only version of the following page on https://raymii.org:
---
Title : File versioning and deleting on OpenVMS with DELETE and PURGE
Author : Remy van Elst
Date : 15-04-2018
URL : https://raymii.org/s/blog/File_versioning_and_deleting_on_OpenVMS.html
Format : Markdown/HTML
---
[![openvms][1]][2]
(You can read all my OpenVMS articles by [clicking the picture above][2])
I'm now a few weeks into my OpenVMS adventure and my home folder on the
[DECUS][3] system is quite cluttered with files. More specifically, with
different versions of files, since OpenVMS by default has file versioning built
in. This means that when you edit a file, or copy a file over an existing file,
the old file is not overwritten but a new file with a new version is written.
The old file still is there. This is one of the best things in my humble opinion
so far on OpenVMS, but it does require maintenance to not have the disk get
filled up fast. This article goes into the PURGE and DELETE commands which help
you deal with file versioning and removal.
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### DIR flags
My home folder [DECUS][3] is getting filled up with test files and other
titbits.
$ DIR /SIZE /OWNER /DATE /PROTECTION
Look at those fancy new flags I found to get more information out of DIR:
Directory DSA3:[DECUSERVE_USER.EXAMPLE]
$MAIN.TPU$JOURNAL;1
1 28-MAR-2018 07:42:31.09 [EXAMPLE] (RWED,RWED,,)
.VIMINFO;1 10 15-APR-2018 08:39:53.81 [EXAMPLE] (RWED,RWED,,)
A.;1 1 8-APR-2018 05:30:44.16 [EXAMPLE] (RWED,RWED,,)
ICREATEDAFOLDERYAY.DIR;1
1 28-MAR-2018 08:22:18.41 [EXAMPLE] (RWE,RWE,,)
LOGIN.COM;2 2 8-APR-2018 06:02:12.72 [EXAMPLE] (RWED,RWED,,)
LOGIN.COM;1 2 1-MAR-2018 10:10:32.12 [EXAMPLE] (RWED,RWED,,)
LOGIN_COM.TPU$JOURNAL;1
1 8-APR-2018 06:00:38.04 [EXAMPLE] (RWED,RWED,,)
MAIL.DIR;1 1 8-APR-2018 16:28:23.24 [EXAMPLE] (RWE,RWE,,)
NOTES$NOTEBOOK.NOTE;1
51 1-MAR-2018 09:56:04.63 [DECUSERVE] (RWE,RWE,,)
RAYMII.DIR;1 1 31-MAR-2018 14:29:02.15 [EXAMPLE] (RWE,RWE,,)
REMY.DAT;8 1 15-APR-2018 08:39:53.79 [EXAMPLE] (RWED,RWED,,)
REMY.DAT;7 1 15-APR-2018 08:39:47.90 [EXAMPLE] (RWED,RWED,,)
REMY.DAT;6 1 15-APR-2018 08:39:12.75 [EXAMPLE] (RWED,RWED,,)
REMY.DAT;5 1 15-APR-2018 08:39:05.02 [EXAMPLE] (RWED,RWED,,)
REMY.DAT;4 1 15-APR-2018 08:38:44.90 [EXAMPLE] (RWED,RWED,,)
REMY.DAT;3 1 31-MAR-2018 14:44:31.08 [EXAMPLE] (RWED,RWED,,)
REMY.DAT;2 1 28-MAR-2018 07:52:19.04 [EXAMPLE] (RWED,RWED,,)
REMY.DAT;1 1 28-MAR-2018 07:48:21.66 [EXAMPLE] (RWED,RWED,,)
SSH.DIR;1 1 3-APR-2018 15:27:07.45 [EXAMPLE] (RWE,RWE,,)
SSH2.DIR;1 1 3-APR-2018 13:16:46.97 [EXAMPLE] (RWE,RWE,,)
SSH3.DIR;1 1 5-APR-2018 13:10:06.94 [EXAMPLE] (RWE,RWE,,)
WWW.DIR;1 1 28-MAR-2018 07:43:47.18 [EXAMPLE] (RWE,RWE,,RE)
Total of 22 files, 83 blocks.
Lets focus on the `REMY.DAT` file, that has 8 versions and all the old ones can
be removed.
### Look at the files with TYPE
Using the `TYPE` command we can look at a file. Specify the full filename and a
specific version number, otherwise if you omit the version you will see the last
version:
$ TYPE REMY.DAT;1
Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.
hello
Version 4:
$ TYPE REMY.DAT;4
Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.
Beware the Jabberwock, my son!
The jaws that bite, the claws that catch!
Beware the Jubjub bird, and shun
The frumious Bandersnatch!
The last version:
$ TYPE REMY.DAT;8
Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.
Beware the Jabberwock, my son!
The jaws that bite, the claws that catch!
Beware the Jubjub bird, and shun
The frumious Bandersnatch!
He took his vorpal sword in hand:
Long time the manxome foe he sought-
So rested he by the Tumtum tree,
And stood awhile in thought.
And as in uffish thought he stood,
The Jabberwock, with eyes of flame,
Came whiffling through the tulgey wood,
And burbled as it came!
One, two! One, two! And through and through
The vorpal blade went snicker-snack!
He left it dead, and with its head
He went galumphing back.
And hast thou slain the Jabberwock?
Come to my arms, my beamish boy!
O frabjous day! Callooh! Callay!
He chortled in his joy.
Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.
(For those who do [not get][5] the reference).
As you can see, the poem is finished in the last versions and the earlier
versions are working copies that can be removed now that this poem is done.
### PURGE
The [PURGE command][6] removes all but the highest version of a file. The
`DELETE` command, which we will cover in the next section, only removes specific
files and it requires you to specify a version number as well.
The `PURGE` command is therefore usefull to clean up old versions of a file.
There are a few usefull flags, for example the `/SINCE` flag. It removes only
the versions from after the specified time. Lets say I worked on a file the
whole week but all versions that were created yesterday and today only contain
formatting fixes, I would specify the `PURGE /SINCE=YESTERDAY $FILE`. The
versions of earlier in the week which do contain changes I want to keep, will be
saved that way.
The opposite of that flags is `/BEFORE` flag. It removes all versions of a file
before the given time. If I wanted to save all versions that I created yesterday
and today, but remove all earlier versions, the command would be `PURGE
/BEFORE=YESTERDAY $FILE`.
If you do want to keep some versions, the `/KEEP` flag allows you to specify a
number of versions to keep. To keep the 5 last versions, specify `/KEEP=5`.
The `/LOG` flag shows you the result, thus which files were removed. By default
no output is logged.
So for my poem, to remove all versions but the last:
$ PURGE /LOG REMY.DAT
%PURGE-I-FILPURG, DSA3:[DECUSERVE_USER.EXAMPLE]REMY.DAT;7 deleted (3 blocks)
%PURGE-I-FILPURG, DSA3:[DECUSERVE_USER.EXAMPLE]REMY.DAT;6 deleted (3 blocks)
%PURGE-I-FILPURG, DSA3:[DECUSERVE_USER.EXAMPLE]REMY.DAT;5 deleted (3 blocks)
%PURGE-I-FILPURG, DSA3:[DECUSERVE_USER.EXAMPLE]REMY.DAT;4 deleted (3 blocks)
%PURGE-I-FILPURG, DSA3:[DECUSERVE_USER.EXAMPLE]REMY.DAT;3 deleted (3 blocks)
%PURGE-I-FILPURG, DSA3:[DECUSERVE_USER.EXAMPLE]REMY.DAT;2 deleted (3 blocks)
%PURGE-I-FILPURG, DSA3:[DECUSERVE_USER.EXAMPLE]REMY.DAT;1 deleted (3 blocks)
%PURGE-I-TOTAL, 7 files deleted (21 blocks)
#### Create a directory with version limits
Using the `/VERSION_LIMIT` flag when creating a folder limits the amount of
versions that will be kept. By default it is unlimited. To create a folder named
`THREE` where at max 3 versions are kept, use the following command:
$ CREATE /DIRECTORY /VERSION_LIMIT=3 [.THREE]
$ SET DEF [.THREE]
I have edited my `REMY.DAT` file three times:
$ DIR
Directory DSA3:[DECUSERVE_USER.EXAMPLE.THREE]
REMY.DAT;3 REMY.DAT;2 REMY.DAT;1
Now after a new edit, version 1 of the file will be gone:
$ DIR
Directory DSA3:[DECUSERVE_USER.EXAMPLE.THREE]
REMY.DAT;4 REMY.DAT;3 REMY.DAT;2
Total of 3 files.
To create a folder without versioning, specify `/VERSION_LIMIT=1`.
Combining that with the previous section, if I wanted to keep the two last
versions, I would use the following command:
$ PURGE /LOG /KEEP=2 REMY.DAT
%PURGE-I-FILPURG, DSA3:[DECUSERVE_USER.EXAMPLE.THREE]REMY.DAT;2 deleted (3 blocks)
Let's check if versions 3 and 4 are still there:
$ DIR
Directory DSA3:[DECUSERVE_USER.EXAMPLE.THREE]
REMY.DAT;4 REMY.DAT;3
Total of 2 files.
### DELETE
You can read most of my delete adventures [here when I tried to remove a
folder][7].
[Reading the documentation][8] on `DELETE`, the same usefull flags like
`/BEFORE` and `/SINCE` can be used. However, they will not remove previous
versions, but all previous files and must be used with wildcards:
/BEFORE[=time]
Selects only those files dated prior to the specified time. You can specify time as absolute time, as a combination of absolute and delta times, or as one of the following keywords: BOOT, LOGIN, TODAY (default), TOMORROW, or YESTERDAY.
Even back then they were already not actually removing a file, but just marking
the location as usable again. The `/ERASE` flag also overwrites the files with
something so that the data actually is not on the disk and not recoverable
anymore:
/ERASE
/NOERASE (default)
When you delete a file, the area in which the file was stored is returned to the system for future use. The data that was stored in that location still exists in the system until new data is written over it. When you specify the /ERASE qualifier, the storage location is overwritten with a system specified pattern so that the data no longer exists.
The `rm -rf` alternative for OpenVMS seems to be the `/TREE` flag:
/TREE
Recursively deletes all files and sub directories excluding the parent directory.
As said, `DELETE` requires a version number. Just trying to delete my `REMY.DAT`
file will fail:
$ DELETE REMY.DAT
%DELETE-E-DELVER, explicit version number or wild card required
When a version is specified it does work:
$ DELETE /LOG REMY.DAT;4
%DELETE-I-FILDEL, DSA3:[DECUSERVE_USER.EXAMPLE.THREE]REMY.DAT;4 deleted (3 blocks)
### Conclusion
In this article we covered the different ways to cleanup versions of files, in
the other article we covered the removal of directories.
We also know now how to create a folder with limits on the amount of versions
that are kept.
[1]: https://raymii.org/s/inc/img/ovmsdec.png
[2]: https://raymii.org/s/tags/openvms.html
[3]: http://decus.org
[4]: https://www.digitalocean.com/?refcode=7435ae6b8212
[5]: https://en.wikipedia.org/wiki/Jabberwocky
[6]: http://web.archive.org/web/20180415125506/http://h41379.www4.hpe.com/doc/84final/9996/9996pro_159.html
[7]: https://raymii.org/s/blog/Delete_a_directory_in_OpenVMS.html
[8]: http://web.archive.org/web/20180415131447/http://h41379.www4.hpe.com/doc/84final/9996/9996pro_50.html
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