1 02/07/85  compare_ascii, cpa
 2 
 3 Syntax as a command:  cpa paths {-control_args}
 4 
 5 
 6 Function: compares ASCII segments and prints any differences.
 7 
 8 An exec_com tool called compare_pl1 compares PL/I source segments of
 9 dissimilar formats via the format_pl1 command (see compare_pl1).
10 
11 
12 Arguments:
13 paths
14    are the pathnames of the segments to be compared.  The equals and
15    archive component pathname conventions are allowed.  Up to six
16    segments can be compared, in addition to the original if one is
17    supplied.  The equal convention can be used in any pathname except
18    the first one on the command line, which is assumed to be the
19    original unless otherwise specified.
20 
21 
22 Control arguments:
23 -extend
24    when -output_file is given, the output is appended to the output
25    file if it already exists.  (Default)
26 -header, -he
27    prints a heading, giving the full pathname and identifying letter of
28    each segment.  This heading is not printed by default.
29 -minchars NN
30    specifies the minimum number of characters that must be identical
31    for compare_ascii to assume that it has found the end of a
32    difference (see "Notes").  (Default: 20)
33 -minlines NN
34    specifies the minimum number of lines that must be identical for
35    compare_ascii to assume that it has found the end of a difference
36    (see "Notes").  (Default: 2)
37 
38 
39 -no_header, -nhe
40    does not print the header information.  (Default)
41 -no_numbers, -nnb
42    does not print identifying letter and line numbers preceding the
43    lines from the segments being compared.  (Default: to print them)
44 -no_original, -no_orig
45    indicates that no original segment is supplied.  If neither
46    -no_original nor -original is given, the first pathname on the
47    command line is assumed to be the original.
48 -no_output_file, -nof
49    specifies that output is to be printed on the terminal.  (Default)
50 -no_totals, -ntt
51    does not print the totals line.
52 
53 
54 -original pathA, -orig pathA
55    specifies the pathname pathA of the original segment of which the
56    others are modified versions.
57 -output_file path, -of path
58    directs the output of the comparison to the file specified by path.
59    The equal convention is allowed, and is applied to the original
60    path.
61 -print_new_lines, -pnl
62    prints only new lines.  New lines are lines found in one or more of
63    the modified versions but not in the original.  An original must be
64    supplied if this argument is used.
65 
66 
67 -totals, -tt
68    prints only the totals line, giving the number of differences and
69    the number of changed lines.  (Default: to print discrepancies and
70    the totals line)
71 -truncate, -tc
72    specifies that the output file be truncated before the comparison is
73    written into it.
74 
75 
76 Notes: The output is organized with the assumption that the pathA
77 segment was edited to produce pathB.  This command prints lines that
78 were added, replaced, or deleted; it identifies each line by line
79 number within the respective segment and also by the letter A or B to
80 indicate which segment the line is from (A for pathA and B for pathB).
81 
82 Values for minchars and minlines can be specified without being
83 preceded by control arguments.  The order is: minchars minlines.
84 
85 
86 The values of minchars and minlines control the size of displayed
87 differences.  Large values for these parameters cause small,
88 closely-spaced differences to be displayed as one large difference,
89 while very small values (such as -minlines 1 -minchars 2) will cause
90 small changes to be displayed individually but might also cause large
91 differences to be broken down into small parts, thereby giving a
92 misleading picture of what was actually done to produce the modified
93 versions.  The user should adjust these parameters to produce the most
94 useful results.