Compares the contents of two disk files and displays a listing of
the records that do not match.
Format
DIFFERENCES input1-filespec [input2-filespec]
1 – Parameters
input1-filespec
Specifies the first file to be compared. The file specification
must include a file name and a file type. The asterisk (*) and
the percent sign (%) wildcard characters are not allowed.
input2-filespec
Specifies the second file to be compared. Unspecified fields
default to the corresponding fields in the input1-filespec
parameter. The asterisk (*) and the percent sign (%) wildcard
characters are not allowed.
If you do not specify a secondary input file, the DIFFERENCES
command uses the next lower version of the primary input file.
2 – Qualifiers
2.1 /CHANGE_BAR
/CHANGE_BAR[=([change-char][,[NO]NUMBER])]
Marks differences using the specified character. The /CHANGE_BAR
qualifier displays output that depends on where the qualifier is
placed. The following examples describe the result of /CHANGE_BAR
qualifier placement.
The following placement displays the latest version of input.file
with the pound sign (#) preceding any lines that differ from the
preceding version of input.file:
$ DIFFERENCES input.file/CHANGE_BAR=#
The following placement displays input.file;2 with the pound sign
(#) preceding any lines that differ from input.file;1:
$ DIFFERENCES input.file;1 input.file;2 /CHANGE_BAR=#
The following placement displays input.file;1 with the pound sign
(#) preceding any lines that differ from input.file;2:
$ DIFFERENCES input.file;1/CHANGE_BAR=# input.file;2
The following placement displays input.file;1 with the percent
sign (%) preceding any lines that differ from input.file;2, and
also displays input.file;2 with the pound sign (#) preceding any
lines that differ from input.file;1:
$ DIFFERENCES input.file;1/CHANGE_BAR=% input.file;2/CHANGE_BAR=#
o If you do not specify a change bar character, the default is
an exclamation point (!) for ASCII output.
o If you specify hexadecimal or octal output (see the
description of the /MODE qualifier), the change bar character
is ignored and differences are marked by a "***CHANGE***"
string in the record header. The keyword NONUMBER suppresses
line numbers in the listing.
o If neither the NUMBER nor the NONUMBER keyword is specified,
the default is controlled by the /[NO]NUMBER command
qualifier.
o If you specify only one option, you can omit the parentheses.
o If you use an exclamation point (!) as the specified
character, you must enclose it in quotation marks (" "); for
example, /CHANGE_BAR=("!",NUMBER).
2.2 /COMMENT_DELIMITER
/COMMENT_DELIMITER[=(character[,...])]
Ignores characters on a line to the right of (and including) a
specified comment character.
If you specify just one character, you can omit the parentheses.
Lowercase characters are automatically converted to uppercase
unless they are enclosed in quotation marks. Nonalphanumeric
characters (such as ! and ,) must be enclosed in quotation
marks. Multicharacter comment characters are not allowed. You
can specify up to 32 comment characters by typing the character
itself or one of the following keywords. (Keywords can be
abbreviated provided that the resultant keyword is not ambiguous
and has at least 2 characters; single letters are treated as
delimiters.)
Keyword Character
COLON Colon (:)
COMMA Comma (,)
EXCLAMATION Exclamation point (!)
FORM_FEED Form feed
LEFT Left bracket ([)
RIGHT Right bracket (])
SEMI_COLON Semicolon (;)
SLASH Slash (/)
SPACE Space
TAB Tab
If you specify the /COMMENT_DELIMITER qualifier, the
/IGNORE=COMMENTS qualifier is implicitly also included.
If both the uppercase and lowercase forms of a letter are to be
used as comment characters, the letter must be specified twice,
once in uppercase and once in lowercase. If you do not include
either a comment character or a keyword with the /COMMENT_
DELIMITER qualifier, the DIFFERENCES command assumes a default
comment character based on the file type. For some file types
(.COB and .FOR), the default comment characters are considered
valid delimiters only if they appear in the first column of a
line.
The following characters are the default comment delimiters for
files with the specified file types:
File Type Default Comment Character
.B2S, .B32, !
.BAS, .BLI
.CBL, .CMD ! and ;
.COB * or / in the first column
.COM, .COR !
.FOR ! anywhere and C, D, c, d in the first column
.HLP !
.MAC, .MAR ;
.R32, .REQ !
2.3 /EXACT
Use with the /PAGE=SAVE and /SEARCH qualifiers to specify a
search string that must match the search string exactly and must
be enclosed with quotation marks (" ").
If you specify the /EXACT qualifier without the /SEARCH
qualifier, exact search mode is enabled when you set the search
string with the Find (E1) key.
2.4 /HIGHLIGHT
/HIGHLIGHT[=keyword]
Use with the /PAGE=SAVE and /SEARCH qualifiers to specify the
type of highlighting you want when a search string is found. When
a string is found, the entire line is highlighted. You can use
the following keywords: BOLD, BLINK, REVERSE, and UNDERLINE. BOLD
is the default highlighting.
2.5 /IGNORE
/IGNORE=(keyword[,...])
Inhibits the comparison of the specified characters, strings,
or records; also controls whether the comparison records are
output to the listing file as edited records or exactly as they
appeared in the input file. If you specify only one keyword, you
can omit the parentheses. The keyword parameter refers to either
a character or a keyword. The first set of keywords determines
what, if anything, is ignored during file comparison; the second
set of keywords determines whether or not ignored characters are
included in the output. The following keywords are valid options
for the /IGNORE qualifier:
Keyword Item Ignored
BLANK_LINES Blank lines between data lines.
CASE Case of the text being compared.
COMMENTS Data following a comment character. (Use the
/COMMENT_DELIMITER qualifier to designate one or
more nondefault comment delimiters.)
FORM_FEEDS Form feed character.
HEADER[=n] Defines n records of the file as header records,
beginning with a record whose first character is
a form feed. The first record is not ignored if
the only character it contains is a form feed.
(n indicates the header size and defaults to 2.
A record containing only a single form feed is
not counted in n.)
SPACING Extra spaces or tabs within data lines.
TRAILING_SPACES Space and tab characters at the end of a data
line.
WHITE_SPACE All spaces and tab characters.
Keyword Status of Ignored Items in Output
EDITED Omits ignored characters from the output
records.
EXACT Includes ignored characters in the output
records.
PRETTY Formats output records.
Each data line is checked for COMMENTS, FORM_FEEDS, HEADER,
and SPACING before it is tested for TRAILING_SPACES and then
BLANK_LINES. Therefore, if you direct the DIFFERENCES command to
ignore COMMENTS, TRAILING_SPACES, and BLANK_LINES, it ignores a
record that contains several spaces or blank lines followed by a
comment.
By default, the DIFFERENCES command compares every character
in each file and reports all differences. Also, by default, the
DIFFERENCES command lists records in the output file with all
ignored characters deleted.
If you specify the /PARALLEL qualifier, output records are always
formatted. The following table shows the corresponding output for
the various characters that are being translated:
Character Formatted Output
Tab (Ctrl/I) 1-8 spaces
Return (Ctrl/M) <CR>
Line feed (Ctrl/J) <LF>
Vertical tab (Ctrl/K) <VT>
Form feed (Ctrl/L) <FF>
Other nonprinting . (period)
characters
2.6 /MATCH
/MATCH=size
Specifies the number of records that should indicate matching
data after a difference is found. By default, after the
DIFFERENCES command finds unmatched records, it assumes that the
files once again match after it finds three sequential records
that match. Use the /MATCH qualifier to override the default
match size of 3.
You can increase the /MATCH qualifier value if you feel that
the DIFFERENCES command is incorrectly matching sections of
the master and revision input files after it has detected a
difference.
2.7 /MAXIMUM_DIFFERENCES
/MAXIMUM_DIFFERENCES=n
Terminates the DIFFERENCES command after the specified number of
unmatched records (specified with the n parameter) is found.
The number of unmatched records is determined by finding the
maximum number of difference records for each difference section
and adding them together.
If the DIFFERENCES command reaches the maximum number of
differences that you specify, it will output only those records
that were detected before the maximum was reached. Also, it will
output, at most, one listing format and return a warning message.
By default, there is no maximum number of differences. All
records in the specified input files are compared.
2.8 /MERGED
/MERGED[=n]
Specifies that the output file contain a merged list of
differences with the specified number of matched records
listed after each group of unmatched records. The value of the
parameter n must be less than or equal to the number specified
in the /MATCH qualifier. By default, the DIFFERENCES command
produces a merged listing with one matched record listed after
each set of unmatched records (that is, /MERGED=1). If the
/MERGED, /SEPARATED, or /PARALLEL qualifier is not specified,
the resulting output is merged, with one matched record following
each unmatched record.
Use the /MERGED qualifier to override the default value of the
parameter n, or to include a merged listing with other types of
output.
2.9 /MODE
/MODE=(radix[,...])
Specifies the format of the output. You can request that the
output be formatted in one or more radix modes by specifying the
following keywords, which may be abbreviated: ASCII (default),
HEXADECIMAL, or OCTAL. If you specify only one radix, you can
omit the parentheses.
By default, the DIFFERENCES command writes the output file in
ASCII. If you specify more than one radix, the output listing
contains the file comparison in each specified radix. When you
specify two or more radix modes, separate them with commas.
If you specify the /PARALLEL or the /SLP qualifier, the /MODE
qualifier is ignored for that listing form.
2.10 /NUMBER
/NUMBER (default)
/NONUMBER
Includes line numbers in the listing of DIFFERENCES.
2.11 /OUTPUT
/OUTPUT[=filespec]
Specifies an output file to receive the list of differences.
By default, the output is written to the current SYS$OUTPUT
device. If the filespec parameter is not specified, the output
is directed to the first input file with a file type .DIF. The
asterisk (*) and the percent sign (%) wildcard characters are not
allowed.
When you specify the /OUTPUT qualifier, you can control the
defaults applied to the output file specification as described
in the OpenVMS User's Manual. The default output file type is
.DIF.
2.12 /PAGE
/PAGE[=keyword]
/NOPAGE (default)
Controls the display of difference information on the screen.
You can use the following keywords with the /PAGE qualifier:
CLEAR_SCREEN Clears the screen before each page is displayed.
SCROLL Displays information one line at a time.
SAVE[=n] Enables screen navigation of information, where n
is the number of pages to store.
The /PAGE=SAVE qualifier allows you to navigate through screens
of information. The /PAGE=SAVE qualifier stores up to 5 screens
of up to 255 columns of information. When you use the /PAGE=SAVE
qualifier, you can use the following keys to navigate through the
information:
Key Sequence Description
Up arrow key, Ctrl/B Scroll up one line.
Down arrow key Scroll down one line.
Left arrow key Scroll left one column.
Right arrow key Scroll right one column.
Find (E1) Specify a string to find when the
information is displayed.
Insert Here (E2) Scroll right one half screen.
Remove (E3) Scroll left one half screen.
Select (E4) Toggle 80/132 column mode.
Prev Screen (E5) Get the previous page of information.
Next Screen (E6), Get the next page of information.
Return, Enter, Space
F10, Ctrl/Z Exit. (Some utilities define these
differently.)
Help (F15) Display utility help text.
Do (F16) Toggle the display to oldest/newest
page.
Ctrl/W Refresh the display.
The /PAGE qualifier is not compatible with the /OUTPUT qualifier.
2.13 /PARALLEL
/PARALLEL[=n]
Lists the records with differences side by side. The value of
the parameter n specifies the number of matched records to merge
after each unmatched record; it must be a non-negative decimal
number less than or equal to the number specified in the /MATCH
qualifier.
By default, the DIFFERENCES command does not list records after
each list of unmatched records. Also by default, the DIFFERENCES
command creates only a list of merged differences.
2.14 /SEARCH
/SEARCH="string"
Use with the /PAGE=SAVE qualifier to specify a string that you
want to find in the information being displayed. Quotation marks
are required for the /SEARCH qualifier, if you include spaces in
the text string.
You can also dynamically change the search string by pressing the
Find key (E1) while the information is being displayed. Quotation
marks are not required for a dynamic search.
2.15 /SEPARATED
/SEPARATED[=MASTER, REVISION]
Lists sequentially only the records from the specified file
that contain differences. Use the MASTER keyword to list the
differences in the first input file specified; use the REVISION
keyword to list the differences in the second input file
specified.
By default, the DIFFERENCES command creates only a merged list of
differences.
2.16 /SLP
Requests that the DIFFERENCES command produce an output file
suitable for input to the SLP editor. If you use the /SLP
qualifier, you cannot specify any of the following output file
qualifiers: /MERGED, /PARALLEL, /SEPARATED, or /CHANGE_BAR.
Use the output file produced by the SLP qualifier as input to
SLP to update the master input file, that is, to make the master
input file match the revision input file.
When you specify the /SLP qualifier and you do not specify the
/OUTPUT qualifier, the DIFFERENCES command writes the output file
to a file with the same file name as the master input file with
the file type DIF.
2.17 /WIDTH
/WIDTH=n
Specifies the width of the lines in the output file. The default
is 132 characters. If output is written to the terminal, the
/WIDTH qualifier is ignored and the terminal line width is used.
Use the SET TERMINAL command to change the terminal line width.
2.18 /WINDOW
/WINDOW=size
Searches the number of records specified by the size parameter,
before a record is declared as unmatched. By default, the
DIFFERENCES command searches to the ends of both input files
before listing a record as unmatched.
The window size is the minimum size of a differences section
that will cause the DIFFERENCES command to lose synchronization
between the two input files.
2.19 /WRAP
/WRAP
/NOWRAP (default)
Use with the /PAGE=SAVE qualifier to limit the number of columns
to the width of the screen and to wrap lines that extend beyond
the width of the screen to the next line.
The /NOWRAP qualifier extends lines beyond the width of the
screen and can be seen when you use the scrolling (left and
right) features provided by the /PAGE=SAVE qualifier.
3 – Examples
1.$ DIFFERENCES EXAMPLE.TXT
************
File DISK1:[CHRIS.TEXT]EXAMPLE.TXT;2
1 DEMONSTRATION
2 OF V7.3 DIFFERENCES
3 UTILITY
******
File DISK1:[CHRIS.TEXT]EXAMPLE.TXT;1
1 DEMONSTRETION
2 OF VMS DIFFERENCES
3 UTILITY
************
Number of difference sections found: 1
Number of difference records found: 2
DIFFERENCES/ IGNORE=()/MERGED=1-
DISK1:[CHRIS.TEXT]EXAMPLE.TXT;2-
DISK1:[CHRIS.TEXT]EXAMPLE.TXT;1
In this example, the DIFFERENCES command compares the contents
of the two most recent versions of the file EXAMPLE.TXT in the
current default directory. The DIFFERENCES command compares
every character in every record and displays the results at the
terminal.
2.$ DIFFERENCES/WIDTH=80/MODE=(HEX,ASCII) EXAMPLE.TXT/CHANGE_BAR
************
File DISK1:[CHRIS.TEXT]EXAMPLE.TXT;2
1 ! DEMONSTRATION
2 ! OF V7.3 DIFFERENCES
3 UTILITY
************
************
File DISK1:[CHRIS.TEXT]EXAMPLE.TXT;2
RECORD NUMBER 1 (00000001) LENGTH 14 (0000000E) ***CHANGE***
204E 4F495441 5254534E 4F4D4544 DEMONSTRATION .. 000000
RECORD NUMBER 2 (00000002) LENGTH 19 (00000013) ***CHANGE***
4E455245 46464944 20302E33 5620464F OF V7.3 DIFFEREN 000000
534543 CES............. 000010
RECORD NUMBER 3 (00000003) LENGTH 7 (00000007)
595449 4C495455 UTILITY......... 000000
************
Number of difference sections found: 1
Number of difference records found: 2
DIFFERENCES /WIDTH=80/MODE=(HEX,ASCII)
DISK1:[CHRIS.TEXT]EXAMPLE.TXT;2/CHANGE_BAR-
DISK1:[CHRIS.TEXT]EXAMPLE.TXT;1
The DIFFERENCES command compares the same files as in
Example 1, but lists the differences in both hexadecimal and
ASCII formats. The command also specifies that default change
bars be used in the output. The default change bar notation for
the hexadecimal output is ***CHANGE***. For the ASCII output,
the default change bar character is the exclamation point.
3.$ DIFFERENCES/OUTPUT BOSTON::DISK2:TEST.DAT OMAHA::DISK1:[PGM]TEST.DAT
The DIFFERENCES command compares two remote files and displays
any differences found. The first file is TEST.DAT on remote
node BOSTON. The second file is also named TEST.DAT on remote
node OMAHA. The DIFFERENCES output is located in the file
DISK1:[PGM]TEST.DIF.