Annotation of src/usr.bin/diff/diff.1, Revision 1.51
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1.1 deraadt 29: .\"
1.2 deraadt 30: .\" @(#)diff.1 8.1 (Berkeley) 6/30/93
31: .\"
1.51 ! millert 32: .Dd $Mdocdate: March 8 2021 $
1.1 deraadt 33: .Dt DIFF 1
1.5 jmc 34: .Os
1.1 deraadt 35: .Sh NAME
36: .Nm diff
37: .Nd differential file and directory comparator
38: .Sh SYNOPSIS
39: .Nm diff
1.44 millert 40: .Op Fl abdipTtw
1.6 millert 41: .Oo
1.26 otto 42: .Fl c | e | f |
1.37 sobrado 43: .Fl n | q | u
1.6 millert 44: .Oc
1.36 sobrado 45: .Op Fl I Ar pattern
1.16 millert 46: .Op Fl L Ar label
1.6 millert 47: .Ar file1 file2
48: .Nm diff
1.51 ! millert 49: .Op Fl abdipTtw
1.26 otto 50: .Op Fl I Ar pattern
1.16 millert 51: .Op Fl L Ar label
52: .Fl C Ar number
1.6 millert 53: .Ar file1 file2
54: .Nm diff
1.51 ! millert 55: .Op Fl abditw
1.26 otto 56: .Op Fl I Ar pattern
1.16 millert 57: .Fl D Ar string
1.1 deraadt 58: .Ar file1 file2
59: .Nm diff
1.51 ! millert 60: .Op Fl abdipTtw
1.26 otto 61: .Op Fl I Ar pattern
1.16 millert 62: .Op Fl L Ar label
63: .Fl U Ar number
1.1 deraadt 64: .Ar file1 file2
65: .Nm diff
1.51 ! millert 66: .Op Fl abdiNPprsTtw
1.6 millert 67: .Oo
1.26 otto 68: .Fl c | e | f |
1.37 sobrado 69: .Fl n | q | u
1.6 millert 70: .Oc
1.36 sobrado 71: .Op Fl I Ar pattern
1.11 millert 72: .Bk -words
1.16 millert 73: .Op Fl L Ar label
1.6 millert 74: .Op Fl S Ar name
1.11 millert 75: .Op Fl X Ar file
76: .Op Fl x Ar pattern
77: .Ek
1.1 deraadt 78: .Ar dir1 dir2
79: .Sh DESCRIPTION
80: The
1.5 jmc 81: .Nm
1.1 deraadt 82: utility compares the contents of
83: .Ar file1
84: and
85: .Ar file2
86: and writes to the standard output the list of changes necessary to
87: convert one file into the other.
88: No output is produced if the files are identical.
89: .Pp
1.22 jmc 90: Output options (mutually exclusive):
1.2 deraadt 91: .Bl -tag -width Ds
1.31 jmc 92: .It Fl C Ar number
93: Like
94: .Fl c
95: but produces a diff with
96: .Ar number
97: lines of context.
1.2 deraadt 98: .It Fl c
1.6 millert 99: Produces a diff with 3 lines of context.
1.1 deraadt 100: With
101: .Fl c
102: the output format is modified slightly:
1.21 jmc 103: the output begins with identification of the files involved and
1.1 deraadt 104: their creation dates and then each change is separated
1.26 otto 105: by a line with fifteen
106: .Li * Ns 's .
1.1 deraadt 107: The lines removed from
108: .Ar file1
1.5 jmc 109: are marked with
1.48 schwarze 110: .Sq \-\ \& ;
1.5 jmc 111: those added to
1.1 deraadt 112: .Ar file2
1.5 jmc 113: are marked
1.48 schwarze 114: .Sq +\ \& .
1.5 jmc 115: Lines which are changed from one file to the other are marked in
116: both files with
117: .Sq !\ \& .
1.19 otto 118: Changes which lie within 3 lines of each other are grouped together on
119: output.
1.31 jmc 120: .It Fl D Ar string
121: Creates a merged version of
122: .Ar file1
123: and
124: .Ar file2
125: on the standard output, with C preprocessor controls included so that
126: a compilation of the result without defining
127: .Ar string
128: is equivalent to compiling
129: .Ar file1 ,
130: while defining
131: .Ar string
132: will yield
133: .Ar file2 .
1.2 deraadt 134: .It Fl e
1.5 jmc 135: Produces output in a form suitable as input for the editor utility,
1.1 deraadt 136: .Xr ed 1 ,
137: which can then be used to convert file1 into file2.
138: .Pp
139: Extra commands are added to the output when comparing directories with
140: .Fl e ,
141: so that the result is a
1.5 jmc 142: .Xr sh 1
1.1 deraadt 143: script for converting text files which are common to the two directories
144: from their state in
145: .Ar dir1
146: to their state in
147: .Ar dir2 .
1.2 deraadt 148: .It Fl f
1.5 jmc 149: Identical output to that of the
1.1 deraadt 150: .Fl e
1.5 jmc 151: flag, but in reverse order.
152: It cannot be digested by
1.1 deraadt 153: .Xr ed 1 .
1.2 deraadt 154: .It Fl n
1.5 jmc 155: Produces a script similar to that of
1.1 deraadt 156: .Fl e ,
157: but in the opposite order and with a count of changed lines on each
1.5 jmc 158: insert or delete command.
159: This is the form used by
160: .Xr rcsdiff 1 .
1.13 millert 161: .It Fl q
162: Just print a line when the files differ.
163: Does not output a list of changes.
1.31 jmc 164: .It Fl U Ar number
165: Like
166: .Fl u
167: but produces a diff with
168: .Ar number
169: lines of context.
1.6 millert 170: .It Fl u
171: Produces a
172: .Em unified
173: diff with 3 lines of context.
174: A unified diff is similar to the context diff produced by the
175: .Fl c
176: option.
177: However, unlike with
178: .Fl c ,
179: all lines to be changed (added and/or removed) are present in
180: a single section.
1.2 deraadt 181: .El
1.1 deraadt 182: .Pp
183: Comparison options:
1.2 deraadt 184: .Bl -tag -width Ds
1.11 millert 185: .It Fl a
1.48 schwarze 186: Treat all files as ASCII text.
1.28 jmc 187: Normally
188: .Nm
189: will simply print
190: .Dq Binary files ... differ
191: if files contain binary characters.
192: Use of this option forces
193: .Nm
194: to produce a diff.
1.2 deraadt 195: .It Fl b
1.5 jmc 196: Causes trailing blanks (spaces and tabs) to be ignored, and other
1.1 deraadt 197: strings of blanks to compare equal.
1.22 jmc 198: .It Fl d
199: Try very hard to produce a diff as small as possible.
200: This may consume a lot of processing power and memory when processing
201: large files with many changes.
1.26 otto 202: .It Fl I Ar pattern
203: Ignores changes, insertions, and deletions whose lines match the
204: extended regular expression
205: .Ar pattern .
206: Multiple
207: .Fl I
208: patterns may be specified.
209: All lines in the change must match some pattern for the change to be
210: ignored.
211: See
212: .Xr re_format 7
213: for more information on regular expression patterns.
1.16 millert 214: .It Fl i
215: Ignores the case of letters.
216: E.g.,
217: .Dq A
218: will compare equal to
219: .Dq a .
1.31 jmc 220: .It Fl L Ar label
221: Print
222: .Ar label
223: instead of the first (and second, if this option is specified twice)
224: file name and time in the context or unified diff header.
1.23 otto 225: .It Fl p
226: With unified and context diffs, show with each change
227: the first 40 characters of the last line before the context beginning
228: with a letter, an underscore or a dollar sign.
229: For C source code following standard layout conventions, this will
230: show the prototype of the function the change applies to.
1.31 jmc 231: .It Fl T
232: Print a tab rather than a space before the rest of the line for the
233: normal, context or unified output formats.
234: This makes the alignment of tabs in the line consistent.
1.2 deraadt 235: .It Fl t
1.5 jmc 236: Will expand tabs in output lines.
237: Normal or
1.1 deraadt 238: .Fl c
239: output adds character(s) to the front of each line which may screw up
240: the indentation of the original source lines and make the output listing
1.5 jmc 241: difficult to interpret.
242: This option will preserve the original source's indentation.
1.2 deraadt 243: .It Fl w
1.5 jmc 244: Is similar to
1.1 deraadt 245: .Fl b
1.5 jmc 246: but causes whitespace (blanks and tabs) to be totally ignored.
247: E.g.,
248: .Dq if (\ \&a == b \&)
249: will compare equal to
250: .Dq if(a==b) .
1.2 deraadt 251: .El
1.1 deraadt 252: .Pp
253: Directory comparison options:
1.2 deraadt 254: .Bl -tag -width Ds
1.11 millert 255: .It Fl N
256: If a file is found in only one directory, act as if it was found in the
257: other directory too but was of zero size.
1.12 millert 258: .It Fl P
259: If a file is found only in
260: .Ar dir2 ,
261: act as if it was found in
262: .Ar dir1
263: too but was of zero size.
1.2 deraadt 264: .It Fl r
1.5 jmc 265: Causes application of
266: .Nm
1.1 deraadt 267: recursively to common subdirectories encountered.
1.6 millert 268: .It Fl S Ar name
1.5 jmc 269: Re-starts a directory
270: .Nm
271: in the middle, beginning with file
1.1 deraadt 272: .Ar name .
1.31 jmc 273: .It Fl s
274: Causes
275: .Nm
276: to report files which are the same, which are otherwise not mentioned.
1.11 millert 277: .It Fl X Ar file
278: Exclude files and subdirectories from comparison whose basenames match
279: lines in
280: .Ar file .
281: Multiple
282: .Fl X
283: options may be specified.
284: .It Fl x Ar pattern
285: Exclude files and subdirectories from comparison whose basenames match
286: .Ar pattern .
287: Patterns are matched using shell-style globbing via
288: .Xr fnmatch 3 .
289: Multiple
290: .Fl x
291: options may be specified.
1.2 deraadt 292: .El
1.1 deraadt 293: .Pp
294: If both arguments are directories,
1.5 jmc 295: .Nm
1.1 deraadt 296: sorts the contents of the directories by name, and then runs the
297: regular file
1.5 jmc 298: .Nm
1.1 deraadt 299: algorithm, producing a change list,
300: on text files which are different.
301: Binary files which differ,
302: common subdirectories, and files which appear in only one directory
303: are described as such.
1.25 millert 304: In directory mode only regular files and directories are compared.
1.48 schwarze 305: If a non-regular file such as a device special file or FIFO
1.26 otto 306: is encountered, a diagnostic message is printed.
1.1 deraadt 307: .Pp
308: If only one of
309: .Ar file1
310: and
311: .Ar file2
312: is a directory,
1.5 jmc 313: .Nm
1.1 deraadt 314: is applied to the non-directory file and the file contained in
315: the directory file with a filename that is the same as the
316: last component of the non-directory file.
317: .Pp
1.2 deraadt 318: If either
1.1 deraadt 319: .Ar file1
320: or
321: .Ar file2
322: is
1.42 jmc 323: .Sq - ,
1.1 deraadt 324: the standard input is
325: used in its place.
326: .Ss Output Style
327: The default (without
328: .Fl e ,
329: .Fl c ,
330: or
331: .Fl n
1.5 jmc 332: .\" -C
1.1 deraadt 333: options)
334: output contains lines of these forms, where
335: .Va XX , YY , ZZ , QQ
336: are line numbers respective of file order.
337: .Pp
1.2 deraadt 338: .Bl -tag -width "XX,YYcZZ,QQ" -compact
339: .It Li XX Ns Ic a Ns Li YY
1.1 deraadt 340: At (the end of) line
341: .Va XX
342: of
343: .Ar file1 ,
344: append the contents
345: of line
346: .Va YY
347: of
348: .Ar file2
349: to make them equal.
1.2 deraadt 350: .It Li XX Ns Ic a Ns Li YY,ZZ
1.1 deraadt 351: Same as above, but append the range of lines,
352: .Va YY
353: through
354: .Va ZZ
355: of
356: .Ar file2
357: to line
358: .Va XX
359: of file1.
1.2 deraadt 360: .It Li XX Ns Ic d Ns Li YY
1.1 deraadt 361: At line
362: .Va XX
363: delete
1.5 jmc 364: the line.
365: The value
1.1 deraadt 366: .Va YY
1.5 jmc 367: tells to which line the change would bring
1.1 deraadt 368: .Ar file1
369: in line with
1.47 jmc 370: .Ar file2 .
1.2 deraadt 371: .It Li XX,YY Ns Ic d Ns Li ZZ
1.1 deraadt 372: Delete the range of lines
373: .Va XX
374: through
375: .Va YY
376: in
377: .Ar file1 .
1.2 deraadt 378: .It Li XX Ns Ic c Ns Li YY
1.1 deraadt 379: Change the line
380: .Va XX
381: in
382: .Ar file1
383: to the line
384: .Va YY
385: in
1.5 jmc 386: .Ar file2 .
1.2 deraadt 387: .It Li XX,YY Ns Ic c Ns Li ZZ
1.1 deraadt 388: Replace the range of specified lines with the line
389: .Va ZZ .
1.2 deraadt 390: .It Li XX,YY Ns Ic c Ns Li ZZ,QQ
1.1 deraadt 391: Replace the range
1.26 otto 392: .Va XX , Ns Va YY
1.1 deraadt 393: from
394: .Ar file1
395: with the range
1.26 otto 396: .Va ZZ , Ns Va QQ
1.1 deraadt 397: from
398: .Ar file2 .
1.2 deraadt 399: .El
1.1 deraadt 400: .Pp
401: These lines resemble
402: .Xr ed 1
403: subcommands to convert
404: .Ar file1
405: into
406: .Ar file2 .
407: The line numbers before the action letters pertain to
408: .Ar file1 ;
409: those after pertain to
410: .Ar file2 .
411: Thus, by exchanging
412: .Ic a
413: for
414: .Ic d
415: and reading the line in reverse order, one can also
416: determine how to convert
417: .Ar file2
418: into
419: .Ar file1 .
420: As in
421: .Xr ed 1 ,
422: identical
423: pairs (where num1 = num2) are abbreviated as a single
424: number.
425: .Sh FILES
1.17 millert 426: .Bl -tag -width /tmp/diff.XXXXXXXX -compact
1.26 otto 427: .It Pa /tmp/diff. Ns Ar XXXXXXXX
1.17 millert 428: Temporary file used when comparing a device or the standard input.
429: Note that the temporary file is unlinked as soon as it is created
430: so it will not show up in a directory listing.
1.2 deraadt 431: .El
1.39 jmc 432: .Sh EXIT STATUS
1.1 deraadt 433: The
1.5 jmc 434: .Nm
1.1 deraadt 435: utility exits with one of the following values:
1.2 deraadt 436: .Pp
1.39 jmc 437: .Bl -tag -width Ds -offset indent -compact
1.30 jmc 438: .It 0
1.1 deraadt 439: No differences were found.
1.30 jmc 440: .It 1
1.1 deraadt 441: Differences were found.
1.43 jmc 442: .It >1
1.1 deraadt 443: An error occurred.
1.2 deraadt 444: .El
1.5 jmc 445: .Sh SEE ALSO
446: .Xr cmp 1 ,
447: .Xr comm 1 ,
448: .Xr diff3 1 ,
1.11 millert 449: .Xr ed 1 ,
1.38 schwarze 450: .Xr patch 1 ,
451: .Xr sdiff 1
1.40 jmc 452: .Rs
453: .%A James W. Hunt
454: .%A M. Douglas McIlroy
455: .%T "An Algorithm for Differential File Comparison"
1.50 jsg 456: .%I AT&T Bell Laboratories
1.40 jmc 457: .%J Computing Science Technical Report
1.50 jsg 458: .%N 41
1.40 jmc 459: .%D June 1976
460: .Re
1.15 millert 461: .Sh STANDARDS
462: The
463: .Nm
1.32 jmc 464: utility is compliant with the
1.34 jmc 465: .St -p1003.1-2008
1.15 millert 466: specification.
1.32 jmc 467: .Pp
468: The flags
1.51 ! millert 469: .Op Fl aDdIiLNnPpqSsTtwXx
1.32 jmc 470: are extensions to that specification.
1.5 jmc 471: .Sh HISTORY
472: A
473: .Nm
474: command appeared in
1.49 jsg 475: .At v5 .
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