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10,7/filcom/filcom.hlp
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Comparing Files Using FILCOM
Function
The FILCOM program compares two files and displays any differences.
Generally, this comparison is line-by-line for ASCII files and
word-by-word for binary files. FILCOM determines the type of
comparison to use by examining either the switches specified in the
command string or the extensions of the files. Switches always take
precedence over file extensions.
Format
R FILCOM
*output-file-spec=input-file-spec,input-file-spec/switch
where: * is the FILCOM prompt, file-spec is a valid file
specification, output-file-spec specifies the name and area on
which the results should be stored, and input-file-spec is a
list of the files to be compared.
The FILCOM program takes the following defaults if you omit some of
the above information:
o If you omit the output specification, the output device is
assumed to be TTY:. If you omit the output file
specification, you must still type the equal sign.
o If you specify only the output file name, the default output
device is DSK:.
o If you omit the output file name, the second input file name
is used, unless it is null. In this case, the file name
FILCOM is used.
o If you omit the output file extension, .SCM is used on a
source compare and .BCM is used on a binary compare.
o If you omit the [directory] in either the input or output
file specifications, your default directory is assumed.
o If you omit an input device name, it is assumed to be DSK:.
o If you omit the file name of the second input file, it is
taken from the first input file.
o You must place a dot following the file name of the second
input file to explicitly indicate a null extension if the
extension of the first input file is not null. For example,
to compare FILE.MAC and FILE. (that is, with null
extension), use the following command string:
R FILCOM<RET>
*=FILE.MAC,FILE.
o The second input file specification cannot be null unless a
binary compare is being performed. In a binary compare, if
the first input file is not followed by a comma and a second
input file descriptor, the input file is compared to a zero
file and is output in its entirety. This gives you a method
of listing a binary file. (Refer to Example 4.)
/switch is one of the options listed below. A switch can follow the
input file-specs. The following switches are used for a binary file
comparison:
/E Creates file in executable format.
/H Prints a list of switches available (help text from
device HLP:).
/nL Specifies the lower limit for a partial binary compare
(n is an octal number). This switch, when used with
the /nU switch, allows a binary file to be compared
only within the specified limits.
/Q Prints the message ?FILES ARE DIFFERENT when the files
are different, but does not list the differences. This
switch is useful when you test batch control files for
differences but do not want a log file of these
differences.
/nU Specifies the upper limit for a partial binary compare
(n is an octal number). This switch, when used with
the /nL switch, allows a binary file to be compared
only within the specified limits.
/W Compares files in binary mode without expanding the
files first. This switch is used to compare two binary
files with ASCII extensions.
/X Expands .SAV files before comparing them in binary
mode. This action removes differences resulting from
zero compression.
If you did not specify any switches in the command string, FILCOM
compares the files in the mode the extension implies. FILCOM
recognizes the following extensions as binary:
.APL .ATR .BAC .BIN
.BUG .CAL .CHN .DAE
.DBS .DCR .DMP .EXE
.HGH .LOW .MSB .OVL
.QUC .QUD .QUE .QUF
.REL .RIM .RMT .RTB
.SAV .SCH .SFD .SHR
.SVE .SYM .SYS .UFD
.UNV .XPN
Binary files are compared word by word, starting at word 0, except for
the following cases:
o Files with extensions .SHR and .HGH are assumed to be
high-segment files. Because the word count starts at 400000,
upper and lower limits, if used, must be greater than (or
equal to in the case of the lower limit) 400000.
o Files with extensions .SAV, .LOW, and .SVE are assumed to be
compressed core image files and are expanded before
comparing.
o Files with the extension .EXE are assumed to be in .EXE
format.
Conflicts are resolved by switches or defaults. If a conflict arises
in the absence of switches, the files are assumed to be ordinary
binary files.
The following switches are used for an ASCII source file comparison:
/A Compares files in ASCII mode. This switch is used to
force comparison of two files to be done in ASCII.
/B Compares blank lines. Without this switch, blank lines
are ignored.
/C Ignores comments (all text on a line following a
semicolon) and spacing (spaces and tabs). A line
consisting entirely of comments or spacing is not
treated as if it were a blank line; differences in such
lines are not ignored.
/H Prints a list of switches available (help text from
device HLP:).
/nL Specifies the number of lines that determine a match (n
is an octal number). A match means that n successive
lines in each input file have been found to be
identical. When a match is found, all differences
occurring before the match and after the previous match
are listed. In addition, the first line of the current
match is listed after the differences, to help you
locate the place within each file at which the
differences occurred. The default value for n is 3.
/O Instructs FILCOM to include a label and offset in the
differences listing for ASCII files. There are three
types of messages. One message is:
[;At top of file + nL]
nL, a decimal number, represents the number of lines
from the top of the file that the difference occurs.
If a difference occurs at the top of the file, nL is
not listed. Another message is:
[;At Label + nL]
Label is the MACRO label closest to the difference and
nL represents the decimal number of lines away from the
label that the difference occurs. If the difference
occurs at the label, nL is not listed. The message for
PDP-11 files is:
[;At Label + nL + following label name]
Label is the local label name in the form nn$, nL
represents the decimal number of lines from the local
label where the difference occurs, and following label
name is the name of the block label. The block label
name is listed as further help in locating the
difference, since local label names are not always
unique. If the difference occurs at the label, nL +
following label name are not listed. The label name
for all labels must be in the first ten characters of
the line. Label name refers to file 1.
/Q Prints the message ?FILES ARE DIFFERENT, when the files
are different, but does not list the differences.
/S Ignores spaces and tabs.
/T Instructs FILCOM to generate output even if no
differences are found. Ordinarily, FILCOM does not
produce a list of differences if there are no
differences in the files.
/U Compares in update mode. This means that the output
file consists of the second input file with vertical
bars (or backslashes for 64-character printers) next to
the lines that differ from the first input file. Any
lines found in the first input file but not in the
second are designated by a bullet (o). This feature is
useful when updating a document because the changes
made to the latest edition are flagged with change bars
in the left margin. The latest edition of the document
is the second input file.
FILCOM Output
In most cases, headers consisting of the device, file name, extension,
and creation date of each input file are listed before the differences
are listed. However, headers do not appear on output from the /U
switch (update mode on source compare).
Output from a source compare has the following notation in the left
column of the output after the headers:
n)m
n is the number of the input file, and m is the page number of the
input file (refer to the examples).
The right column lists the differences occurring between matches in
the input files. Following the list of differences, a line identical
in each file is listed for reference purposes.
The output from the /U switch differs from the above-described output
in that the output file created is the second input file with vertical
bars in the left column next to the lines that are different from the
first input file.
The output from a binary compare prints the following line on the
output device when FILCOM encounters a difference between the two
input files:
octal loc 1st file-word 2nd file-word XOR of both words
If the exclusive OR (XOR) of the two words differs only in the right
half, the third word listed is the absolute value of the difference of
the two right halves. This usually indicates an address that changed.
If one input file is shorter than the other, after the end of file is
encountered on the shorter file, the remainder of the longer file is
listed.
Characteristics
The FILCOM program:
Places your terminal at user level.
Destroys your core image.
Requires LOGIN.
Examples
1. You have the following two ASCII files on disk:
.TYPE FILE1.TST<RET>
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
.TYPE FILE2.TST<RET>
A
B
C
G
H
I
1
2
3
N
O
P
Q
R
S
T
U
V
4
5
W
X
Y
Z
To compare the two files and print the differences on your
terminal, use the following sequence.
Run the FILCOM program.
.R FILCOM<RET>
Compare the two files on disk and output the differences on
your terminal. By default, three consecutive identical lines
determine a match.
*=FILE1.TST,FILE2.TST<RET>
FILE 1) DSKC:FILE1.TST[27,5434] CREATED: 0825 dd-mmm-yyyy
FILE 2) DSKC:FILE2.TST[27,5434] CREATED: 0826 dd-mmm-yyyy
1)1 D
1 E
1) F
1) G
****
2)1 G
**************
1)1 J
1) K
1) L
1) M
1) N
****
2)1 1
2) 2
2) 3
2) N
**************
1)1 W
****
2)1 4
2) 5
2) W
**************
%FILES ARE DIFFERENT
2. To compare the two files and print the differences on the
line printer, use the following command. In this example the
number of successive lines that determines a match has been
set to four with the /4L switch.
*/4L = FILE1.TST,FILE2.TST<RET>
FILE 1) DSKC:FILE1.TST[27,5434] CREATED 0825 dd-mmm-yyyy
FILE 2) DSKC:FILE2.TST[27,5434] CREATED 0826 dd-mmm-yyyy
1)1 D
1) E
1) F
1) G
1) H
1) I
1) J
1) K
1) L
1) M
1) N
****
2)1 G
2) H
2) I
2) 1
2) 2
2) 3
2) N
**************
1)1 W
****
2)1 4
2) 5
2) W
**************
%FILES ARE DIFFERENT
3. To compare the two files so that the second input file is
output with vertical bars in the left column next to the
lines that differ from the first input file, use the
following command sequence:
.R FILCOM<RET>
*/U=FILE1.TST,FILE2.TST<RET>
A
B
C
| G
H
I
| 1
| 2
| 3
N
O
P
Q
R
S
T
U
V
| 4
| 5
W
X
Y
Z
%FILES ARE DIFFERENT
File number two is displayed. The lines with vertical bars
indicate the differences between the two files.