HP OpenVMS Systems

File and version specification?

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The Question is:

 
Where can I find a list defining the available options used on file versions.
Ex:
  file.txt;0 Refers to latest version.
  file.txt;-0 refers to oldest version.
 

The Answer is :

 
  From the chapter on files included in the _OpenVMS User's Guide_:
 
4.1.5 File Versions
 
In addition to a file name and file type, every file has a version number.
Version numbers are decimal numbers from 1 to 32,767 that differentiate versions
of a file. When you create a file, the system assigns it the version number 1.
 
You can have several versions of the same file. Unless you specify a version
number, the system uses the highest existing version number of that file. If you
specify the version number 0, the system uses the highest existing version. When
you modify a file with a command, application, or text editor (such as EVE) that
creates a new version of the file, the file name remains the same but the
version number is incremented by one.
 
Precede version numbers with a semicolon or a period. When the system displays
file specifications, it displays a semicolon in front of the file version
number.
 
You can refer to versions of a file in a relative manner by specifying a zero or
a negative version number. Specifying zero locates the latest (highest numbered)
version of the file. Specifying -1 locates the next-most-recent version, -2 the
version before that, and so on. To locate the earliest (lowest numbered) version
of a file, specify -0 as the version number. Note that you cannot create files
with a version number higher than 32767. If you attempt to create a new file
with a version number higher than 32767, you will receive an error message.
 
The /VERSION_LIMIT qualifier for the CREATE/DIRECTORY, SET DIRECTORY, and SET
FILE commands lets you control the number of versions of a file. If you exceed
the version limit, the system automatically purges the lowest version file in
excess of the limit. For example, if the version limit is 5 and you create the
sixth version of a file (ACCOUNTS.DAT;6), the system deletes the first version
of the file (ACCOUNTS.DAT;1). To view the version limit on a file, enter the
DIRECTORY/FULL command. The version limit is listed in the File attributes:
field.
 
 

  

     

     
answer written or last revised on ( 30-MAR-2000 )
     
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