HP OpenVMS Systems Documentation

HP OpenVMS System Management Utilities Reference Manual

Command Qualifier

Compares the save set, device, file, or files specified by the first parameter with the contents of the Files--11 device, file, or files specified by the second parameter and displays an error message if it finds a difference.

Format

/COMPARE file-spec file-spec

/COMPARE save-set-spec file-spec

/IMAGE/COMPARE device-spec device-spec

/IMAGE/COMPARE save-set-spec device-spec

/PHYSICAL/COMPARE device-spec device-spec

/PHYSICAL/COMPARE save-set-spec device-spec

Description

In a BACKUP compare operation, the first parameter can be a Files--11 file or a wildcard character representing a set of files, a BACKUP save set on disk or magnetic tape, a tape device, or a disk device. The second parameter must be a Files--11 disk file, a wildcard character representing a set of files or a Files--11 disk device, unless you specify the command qualifier /PHYSICAL. When you specify /PHYSICAL, and the first parameter specifies a disk device, both disks in the compare operation must be mounted with the /FOREIGN qualifier.

BACKUP displays the following error message if it encounters a difference between files it compares:

%BACKUP-E-VERIFYERR, verification error for ...

Use the /COMPARE qualifier to compare a save set with original files or to compare files or volumes copied using BACKUP with original files. Because BACKUP processes files by blocks, comparing files not produced by BACKUP is likely to cause mismatch errors in files that are apparently identical.

If you do not specify a version number with the file specification, the default is ;* (the asterisk wildcard character), which processes all versions of the file.

Both parameters in a compare operation are input specifiers.

If you are comparing two entire Files--11 volumes, use an image compare operation, as follows:

$ BACKUP/IMAGE/COMPARE DBA1: DBA2:

You cannot use the command qualifier /DELETE or /RECORD in compare operations.

Do not perform compare operations on files that were restored or copied using the output file qualifier /NEW_VERSION because this qualifier causes version numbers to change.

Examples

$ BACKUP/COMPARE JAZZ.DAT BLUES.DAT
      

This example compares two Files--11 files. Because no version number is specified, BACKUP compares all versions of each file.

$ BACKUP/COMPARE/IMAGE MTA0:SWING.BCK DBA2:
      

This example compares an image save set stored on magnetic tape and a Files--11 volume.

Input File-Selection Qualifier

Displays prompts on your terminal for confirmation before processing each file. If you want the file to be processed, enter Y or YES and press Return.

Format

input-specifier/CONFIRM output-specifier

Example

$ BACKUP *.LIS/CONFIRM/LOG  DLA2:LIST.BCK/SAVE_SET
DISK$DEFAULT:[WONDER]CRE.LIS;1, copy? (Y or N): Y
%BACKUP-S-COPIED, copied DISK$DEFAULT:[WONDER]CRE.LIS;1
DISK$DEFAULT:[WONDER]CRETIME.LIS;1, copy? (Y or N): Y
%BACKUP-S-COPIED, copied DISK$DEFAULT:[WONDER]CRETIME.LIS;1
DISK$DEFAULT:[WONDER]EXC.LIS;1, copy? (Y or N): Y
%BACKUP-S-COPIED, copied DISK$DEFAULT:[WONDER]EXC.LIS;1
DISK$DEFAULT:[WONDER]REB.LIS;1, copy? (Y or N): N
DISK$DEFAULT:[WONDER]SETREB.LIS;1, copy? (Y or N): Y
%BACKUP-S-COPIED, copied DISK$DEFAULT:[WONDER]SETREB.LIS;1
DISK$DEFAULT:[WONDER]VERS.LIS;1, copy? (Y or N): N
.
.
.
$
      

This command locates all files with a file type of .LIS and prompts for confirmation before saving each file to LIST.BCK on DLA2. The command qualifier /LOG displays information about each file as it is processed. Note that you must use the output save-set qualifier /SAVE_SET when creating a save set on disk.

Input File-Selection Qualifier

Converts ODS-5 file names to ODS-2 file names. To preserve the output volume as ODS-2, you must also use the /NOINIT qualifier.

Be aware that all ODS-5 file attributes are lost if you convert from an ODS-5 file name to an ODS-2 file name.

You can also use the /NOCONVERT qualifier.

Format

input-specifier/CONVERT output-specifier

Example

$ BACKUP/LOG/CONVERT/IMAGE DKA500: DKA200:[000000]IMAGE.BCK/SAVE
      

The command in this example creates an ODS-2 image save set from an ODS-5 disk. The save set can be read by a system running a version of OpenVMS prior to Version 7.2.

Input or Output Save-Set Qualifier

As an input save-set qualifier, /CRC causes the software cyclic redundancy check (CRC) encoded in the save set's data blocks to be checked (/CRC) or ignored (/NOCRC). If you ignore the CRC encoding, you reduce processing time at the risk of increasing data error.

As an output save-set qualifier, /CRC specifies that software CRC checking code is to be computed and stored in the data blocks of the output save set. To disable CRC checking, use the /NOCRC qualifier.

Input Save-Set Qualifier

See a separate description of /CRC as an output save-set qualifier.

Specifies that the software cyclic redundancy check (CRC) is to be performed.

Format

input-save-set-spec/[NO]CRC output-specifier

Description

The default is /CRC. To disable CRC checking, specify /NOCRC; note that use of /NOCRC reduces processing time but increases the risk of data loss.

Example

$ BACKUP MTA2:988SAVE.BCK/NOCRC []
      

This command restores the save set 988SAVE.BCK to the current default directory, indicated by ([]); the input save-set qualifier /NOCRC disables CRC.

Output Save-Set Qualifier

See a separate description of /CRC as an input save-set qualifier.

Specifies whether the software cyclic redundancy check (CRC) is to be computed and stored in the data blocks of the output save set.

Format

input-specifier output-save-set-spec/[NO]CRC

Description

The default is /CRC. To disable checking, use /NOCRC; note that use of /NOCRC reduces processing time but increases the risk of data loss.

Example

$ BACKUP/RECORD []/SINCE=BACKUP MTA2:988SAVE.BCK/NOCRC
      

This command saves all files in the current default directory that have been created or modified since the last BACKUP/RECORD operation to the save set 988SAVE.BCK; the output save-set qualifier /NOCRC disables cyclic redundancy checking.

Input File-Selection Qualifier

Selects files according to the value of the creation date field in each file header record.

Format

input-specifier/BEFORE=time/CREATED output-specifier

input-specifier/SINCE=time/CREATED output-specifier

Description

You must use either the /BEFORE qualifier or the /SINCE qualifier with /CREATED. The date and time you specify with /BEFORE or /SINCE determine which files should be processed.

You cannot use /CREATED with the /BACKUP, /MODIFIED, or /EXPIRED qualifiers.

Example

$ BACKUP *.SDML/SINCE=YESTERDAY/CREATED DLA2:[SAVEDIR]/SAVE_SET
      

The command in this example saves all files with a file type of .SDML created since yesterday (24 hours before midnight last night).

Command Qualifier

Specifies that a BACKUP save or copy operation is to delete the selected input files from the input volume after all files have been successfully processed.

Format

/DELETE file-spec save-set-spec

Description

The /DELETE qualifier is valid only when used in a BACKUP save or copy operation. You must have sufficient privilege to delete files; if you do not, files protected against deletion are not deleted. If you use the command qualifier /VERIFY with /DELETE, files that fail verification are not deleted.

You cannot use /DELETE with the /PHYSICAL, /RECORD or /COMPARE command qualifiers.

Examples

$ BACKUP/DELETE BOP.DAT MTA0:BOP.BCK/LABEL=DANCE
      

In this example, the file BOP.DAT will be deleted after the save set BOP.BCK is successfully created on MTA0.

$ BACKUP/VERIFY/DELETE RAY.DAT,JOE.DAT,ELLA.DAT MTA0:OSCAR.BCK/LABEL=FRIEND
      

The BACKUP command deletes the selected list of files in this example after saving them to OSCAR.BCK on MTA0 and comparing the output save set with the input files. If BACKUP detects a difference between the contents of the output save set and the input file, the input file is not deleted.

Output Save-Set Qualifier

Specifies the recording density of the output magnetic tape. Use a value that is supported by the magnetic tape drive.

If you do not specify the /DENSITY qualifier, the default density is the current density of the magnetic tape drive. You must specify the output save-set qualifier /REWIND with /DENSITY.

Format

input-specifier output-save-set-spec/DENSITY=keyword

The following table shows shows the densities that are supported for tapes.

Note that tape density keywords cannot be abbreviated.

Description

The value that you specify must be supported by your magnetic tape hardware. If you omit this qualifier, the default density is the current density on the output tape drive.

The /DENSITY qualifier is incompatible with the output save-set qualifier /NOREWIND. You must specify the output save-set qualifier /REWIND to initialize the magnetic tape when using the /DENSITY qualifier. When you specify /DENSITY/REWIND, BACKUP rewinds the tape to the beginning-of-tape. Then BACKUP initializes the tape with the new density, removing access to all data that previously resided on the tape.

Example

$ BACKUP *.PAS MTA2:SAVEPAS.BCK/DENSITY=1600/REWIND/LABEL=PASCAL
      

The magnetic tape on drive MTA2: is initialized. All files with a file type of .PAS in the current default directory are saved to the save set SAVEPAS.BCK. The /DENSITY qualifier sets the recording density to 1600 bits/in.

Command Qualifier

Creates and restores encrypted save sets. Specify the /ENCRYPT qualifier anywhere on the BACKUP command line.

Note Standalone BACKUP, which is a version of the BACKUP utility that runs without the support of the OpenVMS operating system, does not support the /ENCRYPT qualifier.

Format

/ENCRYPT=([key] [,ALGORITHM=algorithm])

Description

Optionally, you can specify either a key name or a key value, but not both. If you have already defined a key value using the DCL command ENCRYPT/CREATE_KEY, you can specify /ENCRYPT=NAME=key-name to identify the key name that was created and stored in the key storage table.

To define a key value interactively, specify /ENCRYPT=VALUE=key-value,
where key-value is one of the following:

• 1 to 243 alphanumeric characters enclosed in quotation marks (""). Dollar signs ($) and underscores (_) are valid characters. The key is not case sensitive.
• A hexadecimal constant using the digits 0 to 9 and A to F.

Note For additional security, specify the /ENCRYPT qualifier with no parameters and press Return. The command prompts you for a key value. When you enter a value, the software does not echo what you type and, for verification, prompts you to retype the value.

ALGORITHM Keyword

Optionally, you can use ALGORITHM=algorithm to specify DES or AES algorithms:

• Data encryption standard (DES)
  Use DES to encrypt the initialization vector and the key you supply. Possible values for algorithm are as follows:
  • DESCBC (default) --- Cipher block chaining
  • DESECB --- Electronic code book
  • DESCFB --- Cipher feedback
• Advanced encryption standard (AES)
  Use an AES algorithm to encrypt both the data and the user-provided key using the AES algorithm. Possible values for algorithm are as follows:
  • AESCBC --- Cipher block chaining
  • AESECB --- Electronic code book
  • AESCFB --- Cipher feedback
  • AESOFB --- Output feedback
  
  You can also specify one of three different lengths for the AES values:

  128
  192
  256

  
  When you use an AES value, BACKUP places the result of the encryption operation in the save set as a BACKUP attribute subrecord of the BACKUP summary record. At the time of a save set restore or listing operation, BACKUP uses the key you supplied to get to the encrypted key to decrypt the data key the initialization vector value.

Using /ENCRYPT and /SAVE_SET Qualifiers

The BACKUP command qualifier /SAVE_SET is both an input save set qualifier and an output save set qualifier, as follows:

• When you specify the /SAVE_SET and /ENCYRPT qualifiers with an output save set specification, BACKUP writes file data (including file names and attributes) in an encrypted form into the save set.
• When you specify /SAVE_SET with an input save set specification, BACKUP uses the decryption key specified to access the file name, attributes, and data from the save set records. The ENCRYPT option decrypts the data files after BACKUP reads the data files from the save set media and processes them according to the remaining qualifiers of the BACKUP command.

Restoring Files

When you encrypt a save set, BACKUP does not store the encryption key in the save set header. Consequently, to decrypt an encrypted save set, specify /ENCRYPT in the restore operation so that BACKUP searches for the data encryption control record.

If you restore an unencrypted save set and mistakenly specify /ENCRYPT, BACKUP ignores the incorrect qualifier. If you try to restore an encrypted save set without the /ENCRYPT qualifier or with a key name, the system displays the following error message:

%BACKUP-F-ENCSAVSET, save set is encrypted, /ENCRYPT must be specified.

BACKUP tries to decrypt an encrypted save set by:

1. Decrypting the encryption data that was saved in an attribute subrecord.
2. Comparing a 32-bit checksum of the decrypted data key with the stored value.
3. If there is a match, BACKUP assumes the data key is valid and restores the save set.
4. If BACKUP finds a mismatch, which is likely if the data key or algorithm you specified in the BACKUP command is incorrect, the utility displays the following error message:

%BACKUP-F-ENCKEYMAT, the supplied decryption key does not yield a readable save set

Examples

$ ENCRYPT/CREATE_KEY my_key "This is my private encryption key"/AES/LOG
%ENCRYPT-S-KEYDEF, key defined for key name = MY_KEY
$ BACKUP *.COM COMS.BCK/SAVE/ENCRYPT=(name=my_key,alg=AES_/LOG)
      

This example creates an encrypted save set.

$ BACKUP *.COM COMS.BCK/SAVE/ENCRY=ALG=AES
Enter key value:
Verification:
$
      

In this example, the BACKUP command line does not contain a key name or key value; therefore, BACKUP prompts for an encryption key.

$ BACKUP DKA100: DKA100.BCK/SAV/IMA/ENCRY=(VALUE="THIS IS MY
ENCRYPTION KEY")
      

In this example, the image BACKUP of DKA100 is encrypted in a save set with a key value that uses the default DESCBC algorithm.

$ BACKUP DKA100: DKA100.BCK/SAV/IMA/ENCRY=(VALUE="THIS IS MY
ENCRYPTION KEY",ALGO=AESCFB192)
      

In this example, the image BACKUP of DKA100 is encrypted in a saveset with a key value that uses the AESCFB algorithm with an 192-bit encryption key.