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30 .\" @(#)diff.1 8.1 (Berkeley) 6/30/93
38 .Nd differential file and directory comparator
47 .Op Fl -changed-group-format Ar GFMT
51 .Op Fl -ignore-all-space
53 .Op Fl -ignore-space-change
56 .Op Fl -no-ignore-file-name-case
59 .Op Fl -show-c-function
61 .Op Fl -speed-large-files
62 .Op Fl -strip-trailing-cr
63 .Op Fl -tabsize Ar number
66 .Op Fl I Ar pattern | Fl -ignore-matching-lines Ar pattern
67 .Op Fl L Ar label | Fl -label Ar label
71 .Op Fl I Ar pattern | Fl -ignore-matching-lines Ar pattern
72 .Op Fl L Ar label | Fl -label Ar label
74 .Op Fl -changed-group-format Ar GFMT
78 .Op Fl -ignore-all-space
80 .Op Fl -ignore-space-change
83 .Op Fl -no-ignore-file-name-case
87 .Op Fl -show-c-function
88 .Op Fl -speed-large-files
90 .Op Fl -strip-trailing-cr
91 .Op Fl -tabsize Ar number
93 .Fl C Ar number | -context Ar number
97 .Op Fl I Ar pattern | Fl -ignore-matching-lines Ar pattern
99 .Op Fl -changed-group-format Ar GFMT
103 .Op Fl -ignore-all-space
105 .Op Fl -ignore-space-change
108 .Op Fl -no-ignore-file-name-case
112 .Op Fl -show-c-function
113 .Op Fl -speed-large-files
114 .Op Fl -starting-file
115 .Op Fl -strip-trailing-cr
116 .Op Fl -tabsize Ar number
118 .Fl D Ar string | Fl -ifdef Ar string
122 .Op Fl I Ar pattern | Fl -ignore-matching-lines Ar pattern
123 .Op Fl L Ar label | Fl -label Ar label
125 .Op Fl -changed-group-format Ar GFMT
129 .Op Fl -ignore-all-space
131 .Op Fl -ignore-space-change
134 .Op Fl -no-ignore-file-name-case
138 .Op Fl -show-c-function
139 .Op Fl -speed-large-files
140 .Op Fl -starting-file
141 .Op Fl -strip-trailing-cr
142 .Op Fl -tabsize Ar number
144 .Fl U Ar number | Fl -unified Ar number
147 .Op Fl aBbdilNPprsTtw
153 .Op Fl -changed-group-format Ar GFMT
158 .Op Fl -ignore-all-space
160 .Op Fl -ignore-space-change
164 .Op Fl -no-ignore-file-name-case
169 .Op Fl -report-identical-files
170 .Op Fl -show-c-function
171 .Op Fl -speed-large-files
172 .Op Fl -strip-trailing-cr
173 .Op Fl -tabsize Ar number
175 .Op Fl -unidirectional-new-file
177 .Op Fl I Ar pattern | Fl -ignore-matching-lines Ar pattern
179 .Op Fl L Ar label | Fl -label Ar label
180 .Op Fl S Ar name | Fl -starting-file Ar name
181 .Op Fl X Ar file | Fl -exclude-from Ar file
182 .Op Fl x Ar pattern | Fl -exclude Ar pattern
188 .Op Fl -ignore-all-blanks
189 .Op Fl -ignore-blank-lines
192 .Op Fl -no-ignore-file-name-case
193 .Op Fl -strip-trailing-cr
194 .Op Fl -suppress-common-lines
195 .Op Fl -tabsize Ar number
198 .Fl y | Fl -side-by-side
203 utility compares the contents of
207 and writes to the standard output the list of changes necessary to
208 convert one file into the other.
209 No output is produced if the files are identical.
211 Output options (mutually exclusive):
213 .It Fl C Ar number Fl -context Ar number
216 but produces a diff with
220 Produces a diff with 3 lines of context.
223 the output format is modified slightly:
224 the output begins with identification of the files involved and
225 their creation dates and then each change is separated
226 by a line with fifteen
228 The lines removed from
236 Lines which are changed from one file to the other are marked in
239 Changes which lie within 3 lines of each other are grouped together on
241 .It Fl D Ar string Fl -ifdef Ar string
242 Creates a merged version of
246 on the standard output, with C preprocessor controls included so that
247 a compilation of the result without defining
249 is equivalent to compiling
256 Produces output in a form suitable as input for the editor utility,
258 which can then be used to convert file1 into file2.
260 Extra commands are added to the output when comparing directories with
262 so that the result is a
264 script for converting text files which are common to the two directories
270 Identical output to that of the
272 flag, but in reverse order.
273 It cannot be digested by
276 Produces a script similar to that of
278 but in the opposite order and with a count of changed lines on each
279 insert or delete command.
280 This is the form used by
283 Just print a line when the files differ.
284 Does not output a list of changes.
285 .It Fl U Ar number Fl -unified Ar number
288 but produces a diff with
294 diff with 3 lines of context.
295 A unified diff is similar to the context diff produced by the
300 all lines to be changed (added and/or removed) are present in
302 .It Fl y Fl -side-by-side
303 Output in two columns with a marker between them.
304 The marker can be one
307 .Bl -tag -width Ds -offset indent -compact
309 Corresponding lines are identical.
311 Corresponding lines are different.
313 Files differ and only the first file contains the line.
315 Files differ and only the second file contains the line.
322 Treat all files as ASCII text.
326 .Dq Binary files ... differ
327 if files contain binary characters.
328 Use of this option forces
331 .It Fl B Fl -ignore-blank-lines
332 Causes chunks that include only blank lines to be ignored.
333 .It Fl b -ignore-space-change
334 Causes trailing blanks (spaces and tabs) to be ignored, and other
335 strings of blanks to compare equal.
337 Try very hard to produce a diff as small as possible.
338 This may consume a lot of processing power and memory when processing
339 large files with many changes.
340 .It Fl I Ar pattern Fl -ignore-matching-lines Ar pattern
341 Ignores changes, insertions, and deletions whose lines match the
342 extended regular expression
346 patterns may be specified.
347 All lines in the change must match some pattern for the change to be
351 for more information on regular expression patterns.
352 .It Fl i -ignore-case
353 Ignores the case of letters.
356 will compare equal to
359 Pass the output through
362 .It Fl L Ar label Fl -label Ar label
365 instead of the first (and second, if this option is specified twice)
366 file name and time in the context or unified diff header.
367 .It Fl p -show-c-function
368 With unified and context diffs, show with each change
369 the first 40 characters of the last line before the context beginning
370 with a letter, an underscore or a dollar sign.
371 For C source code following standard layout conventions, this will
372 show the prototype of the function the change applies to.
373 .It Fl T -initial-tab
374 Print a tab rather than a space before the rest of the line for the
375 normal, context or unified output formats.
376 This makes the alignment of tabs in the line consistent.
377 .It Fl t -expand-tabs
378 Will expand tabs in output lines.
381 output adds character(s) to the front of each line which may screw up
382 the indentation of the original source lines and make the output listing
383 difficult to interpret.
384 This option will preserve the original source's indentation.
385 .It Fl w -ignore-all-blanks
387 .Fl b -ignore-space-change
388 but causes whitespace (blanks and tabs) to be totally ignored.
390 .Dq if (\ \&a == b \&)
391 will compare equal to
393 .It Fl W Ar number Fl -width Ar number
396 columns when using side by side format.
397 The default value is 130.
398 .It Fl -changed-group-format Ar GFMT
399 Format input groups in the provided
401 the format is a string with special keywords:
408 .It Fl -ignore-file-name-case
409 ignore case when comparing file names
410 .It Fl -no-ignore-file-name-case
411 do not ignore case wen comparing file names (default)
414 .It Fl -speed-large-files
415 stub option for compatibility with GNU diff
416 .It Fl -strip-trailing-cr
417 strip carriage return on input files
418 .It Fl -suppress-common-lines
419 Do not output common lines when using the side by side format
420 .It Fl -tabsize Ar number
421 Number of spaces representing a tab (default 8)
424 Directory comparison options:
427 If a file is found in only one directory, act as if it was found in the
428 other directory too but was of zero size.
429 .It Fl P -unidirectional-new-file
430 If a file is found only in
432 act as if it was found in
434 too but was of zero size.
436 Causes application of
438 recursively to common subdirectories encountered.
439 .It Fl S Ar name Fl -starting-file Ar name
440 Re-starts a directory
442 in the middle, beginning with file
444 .It Fl s -report-identical-files
447 to report files which are the same, which are otherwise not mentioned.
448 .It Fl X Ar file Fl -exclude-from Ar file
449 Exclude files and subdirectories from comparison whose basenames match
454 options may be specified.
455 .It Fl x Ar pattern Fl -exclude Ar pattern
456 Exclude files and subdirectories from comparison whose basenames match
458 Patterns are matched using shell-style globbing via
462 options may be specified.
465 If both arguments are directories,
467 sorts the contents of the directories by name, and then runs the
470 algorithm, producing a change list,
471 on text files which are different.
472 Binary files which differ,
473 common subdirectories, and files which appear in only one directory
474 are described as such.
475 In directory mode only regular files and directories are compared.
476 If a non-regular file such as a device special file or FIFO is encountered,
477 a diagnostic message is printed.
485 is applied to the non-directory file and the file contained in
486 the directory file with a filename that is the same as the
487 last component of the non-directory file.
495 the standard input is
505 output contains lines of these forms, where
506 .Va XX , YY , ZZ , QQ
507 are line numbers respective of file order.
509 .Bl -tag -width "XX,YYcZZ,QQ" -compact
510 .It Li XX Ns Ic a Ns Li YY
521 .It Li XX Ns Ic a Ns Li YY,ZZ
522 Same as above, but append the range of lines,
531 .It Li XX Ns Ic d Ns Li YY
538 tells to which line the change would bring
542 .It Li XX,YY Ns Ic d Ns Li ZZ
543 Delete the range of lines
549 .It Li XX Ns Ic c Ns Li YY
558 .It Li XX,YY Ns Ic c Ns Li ZZ
559 Replace the range of specified lines with the line
561 .It Li XX,YY Ns Ic c Ns Li ZZ,QQ
574 subcommands to convert
578 The line numbers before the action letters pertain to
580 those after pertain to
586 and reading the line in reverse order, one can also
587 determine how to convert
594 pairs (where num1 = num2) are abbreviated as a single
597 .Bl -tag -width /tmp/diff.XXXXXXXX -compact
598 .It Pa /tmp/diff.XXXXXXXX
599 Temporary file used when comparing a device or the standard input.
600 Note that the temporary file is unlinked as soon as it is created
601 so it will not show up in a directory listing.
606 utility exits with one of the following values:
608 .Bl -tag -width Ds -offset indent -compact
610 No differences were found.
612 Differences were found.
626 .%A M. Douglas McIlroy
627 .%T "An Algorithm for Differential File Comparison"
628 .%J Computing Science Technical Report
629 .%Q Bell Laboratories 41
635 utility is compliant with the
640 .Op Fl aDdIiLlNnPpqSsTtwXxy
641 are extensions to that specification.