1.\" $OpenBSD: diff.1,v 1.27 2004/12/09 18:56:10 millert Exp $ 2.\" 3.\" Copyright (c) 1980, 1990, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)diff.1 8.1 (Berkeley) 6/30/93 31.\" 32.Dd July 21, 2003 33.Dt DIFF 1 34.Os 35.Sh NAME 36.Nm diff 37.Nd differential file and directory comparator 38.Sh SYNOPSIS 39.Nm diff 40.Op Fl abdilpqtTw 41.Op Fl I Ar pattern 42.Oo 43.Fl c | e | f | 44.Fl n | u 45.Oc 46.Op Fl L Ar label 47.Ar file1 file2 48.Nm diff 49.Op Fl abdilpqtTw 50.Op Fl I Ar pattern 51.Op Fl L Ar label 52.Fl C Ar number 53.Ar file1 file2 54.Nm diff 55.Op Fl abdilqtw 56.Op Fl I Ar pattern 57.Fl D Ar string 58.Ar file1 file2 59.Nm diff 60.Op Fl abdilpqtTw 61.Op Fl I Ar pattern 62.Op Fl L Ar label 63.Fl U Ar number 64.Ar file1 file2 65.Nm diff 66.Op Fl abdilNPpqtTw 67.Op Fl I Ar pattern 68.Oo 69.Fl c | e | f | 70.Fl n | u 71.Oc 72.Bk -words 73.Op Fl L Ar label 74.Op Fl r 75.Op Fl s 76.Op Fl S Ar name 77.Op Fl X Ar file 78.Op Fl x Ar pattern 79.Ek 80.Ar dir1 dir2 81.Sh DESCRIPTION 82The 83.Nm 84utility compares the contents of 85.Ar file1 86and 87.Ar file2 88and writes to the standard output the list of changes necessary to 89convert one file into the other. 90No output is produced if the files are identical. 91.Pp 92Output options (mutually exclusive): 93.Bl -tag -width Ds 94.It Fl c 95Produces a diff with 3 lines of context. 96With 97.Fl c 98the output format is modified slightly: 99the output begins with identification of the files involved and 100their creation dates and then each change is separated 101by a line with fifteen 102.Li * Ns 's . 103The lines removed from 104.Ar file1 105are marked with 106.Sq \&-\ \& ; 107those added to 108.Ar file2 109are marked 110.Sq \+\ \& . 111Lines which are changed from one file to the other are marked in 112both files with 113.Sq !\ \& . 114Changes which lie within 3 lines of each other are grouped together on 115output. 116.It Fl e 117Produces output in a form suitable as input for the editor utility, 118.Xr ed 1 , 119which can then be used to convert file1 into file2. 120.Pp 121Extra commands are added to the output when comparing directories with 122.Fl e , 123so that the result is a 124.Xr sh 1 125script for converting text files which are common to the two directories 126from their state in 127.Ar dir1 128to their state in 129.Ar dir2 . 130.It Fl f 131Identical output to that of the 132.Fl e 133flag, but in reverse order. 134It cannot be digested by 135.Xr ed 1 . 136.It Fl n 137Produces a script similar to that of 138.Fl e , 139but in the opposite order and with a count of changed lines on each 140insert or delete command. 141This is the form used by 142.Xr rcsdiff 1 . 143.It Fl q 144Just print a line when the files differ. 145Does not output a list of changes. 146.It Fl u 147Produces a 148.Em unified 149diff with 3 lines of context. 150A unified diff is similar to the context diff produced by the 151.Fl c 152option. 153However, unlike with 154.Fl c , 155all lines to be changed (added and/or removed) are present in 156a single section. 157.It Fl C Ar number 158Like 159.Fl c 160but produces a diff with 161.Ar number 162lines of context. 163.It Fl D Ar string 164Creates a merged version of 165.Ar file1 166and 167.Ar file2 168on the standard output, with C preprocessor controls included so that 169a compilation of the result without defining 170.Ar string 171is equivalent to compiling 172.Ar file1 , 173while defining 174.Ar string 175will yield 176.Ar file2 . 177.It Fl U Ar number 178Like 179.Fl u 180but produces a diff with 181.Ar number 182lines of context. 183.El 184.Pp 185Comparison options: 186.Bl -tag -width Ds 187.It Fl a 188Treat all files as 189.Tn ASCII . 190.It Fl b 191Causes trailing blanks (spaces and tabs) to be ignored, and other 192strings of blanks to compare equal. 193.It Fl d 194Try very hard to produce a diff as small as possible. 195This may consume a lot of processing power and memory when processing 196large files with many changes. 197.It Fl I Ar pattern 198Ignores changes, insertions, and deletions whose lines match the 199extended regular expression 200.Ar pattern . 201Multiple 202.Fl I 203patterns may be specified. 204All lines in the change must match some pattern for the change to be 205ignored. 206See 207.Xr re_format 7 208for more information on regular expression patterns. 209.It Fl i 210Ignores the case of letters. 211E.g., 212.Dq A 213will compare equal to 214.Dq a . 215.It Fl l 216Long output format; each text file 217.Nm diff Ns \'d 218is piped through 219.Xr pr 1 220to paginate it; 221other differences are remembered and summarized 222after all text file differences are reported. 223.It Fl L Ar label 224Print 225.Ar label 226instead of the first (and second, if this option is specified twice) 227file name and time in the context or unified diff header. 228.It Fl p 229With unified and context diffs, show with each change 230the first 40 characters of the last line before the context beginning 231with a letter, an underscore or a dollar sign. 232For C source code following standard layout conventions, this will 233show the prototype of the function the change applies to. 234.It Fl t 235Will expand tabs in output lines. 236Normal or 237.Fl c 238output adds character(s) to the front of each line which may screw up 239the indentation of the original source lines and make the output listing 240difficult to interpret. 241This option will preserve the original source's indentation. 242.It Fl T 243Print a tab rather than a space before the rest of the line for the 244normal, context or unified output formats. 245This makes the alignment of tabs in the line consistent. 246.It Fl w 247Is similar to 248.Fl b 249but causes whitespace (blanks and tabs) to be totally ignored. 250E.g., 251.Dq if (\ \&a == b \&) 252will compare equal to 253.Dq if(a==b) . 254.El 255.Pp 256Directory comparison options: 257.Bl -tag -width Ds 258.It Fl N 259If a file is found in only one directory, act as if it was found in the 260other directory too but was of zero size. 261.It Fl P 262If a file is found only in 263.Ar dir2 , 264act as if it was found in 265.Ar dir1 266too but was of zero size. 267.It Fl r 268Causes application of 269.Nm 270recursively to common subdirectories encountered. 271.It Fl s 272Causes 273.Nm 274to report files which are the same, which are otherwise not mentioned. 275.It Fl S Ar name 276Re-starts a directory 277.Nm 278in the middle, beginning with file 279.Ar name . 280.It Fl X Ar file 281Exclude files and subdirectories from comparison whose basenames match 282lines in 283.Ar file . 284Multiple 285.Fl X 286options may be specified. 287.It Fl x Ar pattern 288Exclude files and subdirectories from comparison whose basenames match 289.Ar pattern . 290Patterns are matched using shell-style globbing via 291.Xr fnmatch 3 . 292Multiple 293.Fl x 294options may be specified. 295.El 296.Pp 297If both arguments are directories, 298.Nm 299sorts the contents of the directories by name, and then runs the 300regular file 301.Nm 302algorithm, producing a change list, 303on text files which are different. 304Binary files which differ, 305common subdirectories, and files which appear in only one directory 306are described as such. 307In directory mode only regular files and directories are compared. 308If a non-regular file such as a device special file or 309.Tn FIFO 310is encountered, a diagnostic message is printed. 311.Pp 312If only one of 313.Ar file1 314and 315.Ar file2 316is a directory, 317.Nm 318is applied to the non-directory file and the file contained in 319the directory file with a filename that is the same as the 320last component of the non-directory file. 321.Pp 322If either 323.Ar file1 324or 325.Ar file2 326is 327.Sq Fl , 328the standard input is 329used in its place. 330.Ss Output Style 331The default (without 332.Fl e , 333.Fl c , 334or 335.Fl n 336.\" -C 337options) 338output contains lines of these forms, where 339.Va XX , YY , ZZ , QQ 340are line numbers respective of file order. 341.Pp 342.Bl -tag -width "XX,YYcZZ,QQ" -compact 343.It Li XX Ns Ic a Ns Li YY 344At (the end of) line 345.Va XX 346of 347.Ar file1 , 348append the contents 349of line 350.Va YY 351of 352.Ar file2 353to make them equal. 354.It Li XX Ns Ic a Ns Li YY,ZZ 355Same as above, but append the range of lines, 356.Va YY 357through 358.Va ZZ 359of 360.Ar file2 361to line 362.Va XX 363of file1. 364.It Li XX Ns Ic d Ns Li YY 365At line 366.Va XX 367delete 368the line. 369The value 370.Va YY 371tells to which line the change would bring 372.Ar file1 373in line with 374.Ar file1 . 375.It Li XX,YY Ns Ic d Ns Li ZZ 376Delete the range of lines 377.Va XX 378through 379.Va YY 380in 381.Ar file1 . 382.It Li XX Ns Ic c Ns Li YY 383Change the line 384.Va XX 385in 386.Ar file1 387to the line 388.Va YY 389in 390.Ar file2 . 391.It Li XX,YY Ns Ic c Ns Li ZZ 392Replace the range of specified lines with the line 393.Va ZZ . 394.It Li XX,YY Ns Ic c Ns Li ZZ,QQ 395Replace the range 396.Va XX , Ns Va YY 397from 398.Ar file1 399with the range 400.Va ZZ , Ns Va QQ 401from 402.Ar file2 . 403.El 404.Pp 405These lines resemble 406.Xr ed 1 407subcommands to convert 408.Ar file1 409into 410.Ar file2 . 411The line numbers before the action letters pertain to 412.Ar file1 ; 413those after pertain to 414.Ar file2 . 415Thus, by exchanging 416.Ic a 417for 418.Ic d 419and reading the line in reverse order, one can also 420determine how to convert 421.Ar file2 422into 423.Ar file1 . 424As in 425.Xr ed 1 , 426identical 427pairs (where num1 = num2) are abbreviated as a single 428number. 429.Sh ENVIRONMENT 430.Bl -tag -width TMPDIR 431.It Ev TMPDIR 432If the environment variable 433.Ev TMPDIR 434exists, 435.Nm 436will use the directory specified by 437.Ev TMPDIR 438as the temporary directory. 439.El 440.Sh FILES 441.Bl -tag -width /tmp/diff.XXXXXXXX -compact 442.It Pa /tmp/diff. Ns Ar XXXXXXXX 443Temporary file used when comparing a device or the standard input. 444Note that the temporary file is unlinked as soon as it is created 445so it will not show up in a directory listing. 446.El 447.Sh DIAGNOSTICS 448The 449.Nm 450utility exits with one of the following values: 451.Pp 452.Bl -tag -width Ds -compact -offset indent 453.It \&0 454No differences were found. 455.It \&1 456Differences were found. 457.It \*[Gt]\&1 458An error occurred. 459.El 460.Sh SEE ALSO 461.Xr cmp 1 , 462.Xr comm 1 , 463.Xr diff3 1 , 464.Xr ed 1 , 465.Xr pr 1 , 466.Xr fnmatch 3 , 467.Xr re_format 7 468.Sh STANDARDS 469The 470.Nm 471utility is expected to be a superset of the 472.St -p1003.1-2001 473specification. 474.Sh HISTORY 475A 476.Nm 477command appeared in 478.At v6 . 479.Sh BUGS 480When comparing directories with the 481.Fl b , 482.Fl w 483or 484.Fl i 485options specified, 486.Nm 487first compares the files ala 488.Xr cmp 1 , 489and then decides to run the 490.Nm 491algorithm if they are not equal. 492This may cause a small amount of spurious output if the files 493then turn out to be identical because the only differences are 494insignificant whitespace or case differences. 495