.\" $OpenBSD: diff.1,v 1.31 2007/03/01 21:48:32 jmc Exp $ .\" .\" Copyright (c) 1980, 1990, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)diff.1 8.1 (Berkeley) 6/30/93 .\" .Dd July 21, 2003 .Dt DIFF 1 .Os .Sh NAME .Nm diff .Nd differential file and directory comparator .Sh SYNOPSIS .Nm diff .Op Fl abdilpqTtw .Op Fl I Ar pattern .Oo .Fl c | e | f | .Fl n | u .Oc .Op Fl L Ar label .Ar file1 file2 .Nm diff .Op Fl abdilpqTtw .Op Fl I Ar pattern .Op Fl L Ar label .Fl C Ar number .Ar file1 file2 .Nm diff .Op Fl abdilqtw .Op Fl I Ar pattern .Fl D Ar string .Ar file1 file2 .Nm diff .Op Fl abdilpqTtw .Op Fl I Ar pattern .Op Fl L Ar label .Fl U Ar number .Ar file1 file2 .Nm diff .Op Fl abdilNPpqrsTtw .Op Fl I Ar pattern .Oo .Fl c | e | f | .Fl n | u .Oc .Bk -words .Op Fl L Ar label .Op Fl S Ar name .Op Fl X Ar file .Op Fl x Ar pattern .Ek .Ar dir1 dir2 .Sh DESCRIPTION The .Nm utility compares the contents of .Ar file1 and .Ar file2 and writes to the standard output the list of changes necessary to convert one file into the other. No output is produced if the files are identical. .Pp Output options (mutually exclusive): .Bl -tag -width Ds .It Fl C Ar number Like .Fl c but produces a diff with .Ar number lines of context. .It Fl c Produces a diff with 3 lines of context. With .Fl c the output format is modified slightly: the output begins with identification of the files involved and their creation dates and then each change is separated by a line with fifteen .Li * Ns 's . The lines removed from .Ar file1 are marked with .Sq \&-\ \& ; those added to .Ar file2 are marked .Sq \+\ \& . Lines which are changed from one file to the other are marked in both files with .Sq !\ \& . Changes which lie within 3 lines of each other are grouped together on output. .It Fl D Ar string Creates a merged version of .Ar file1 and .Ar file2 on the standard output, with C preprocessor controls included so that a compilation of the result without defining .Ar string is equivalent to compiling .Ar file1 , while defining .Ar string will yield .Ar file2 . .It Fl e Produces output in a form suitable as input for the editor utility, .Xr ed 1 , which can then be used to convert file1 into file2. .Pp Extra commands are added to the output when comparing directories with .Fl e , so that the result is a .Xr sh 1 script for converting text files which are common to the two directories from their state in .Ar dir1 to their state in .Ar dir2 . .It Fl f Identical output to that of the .Fl e flag, but in reverse order. It cannot be digested by .Xr ed 1 . .It Fl n Produces a script similar to that of .Fl e , but in the opposite order and with a count of changed lines on each insert or delete command. This is the form used by .Xr rcsdiff 1 . .It Fl q Just print a line when the files differ. Does not output a list of changes. .It Fl U Ar number Like .Fl u but produces a diff with .Ar number lines of context. .It Fl u Produces a .Em unified diff with 3 lines of context. A unified diff is similar to the context diff produced by the .Fl c option. However, unlike with .Fl c , all lines to be changed (added and/or removed) are present in a single section. .El .Pp Comparison options: .Bl -tag -width Ds .It Fl a Treat all files as .Tn ASCII text. Normally .Nm will simply print .Dq Binary files ... differ if files contain binary characters. Use of this option forces .Nm to produce a diff. .It Fl b Causes trailing blanks (spaces and tabs) to be ignored, and other strings of blanks to compare equal. .It Fl d Try very hard to produce a diff as small as possible. This may consume a lot of processing power and memory when processing large files with many changes. .It Fl I Ar pattern Ignores changes, insertions, and deletions whose lines match the extended regular expression .Ar pattern . Multiple .Fl I patterns may be specified. All lines in the change must match some pattern for the change to be ignored. See .Xr re_format 7 for more information on regular expression patterns. .It Fl i Ignores the case of letters. E.g., .Dq A will compare equal to .Dq a . .It Fl L Ar label Print .Ar label instead of the first (and second, if this option is specified twice) file name and time in the context or unified diff header. .It Fl l Long output format; each text file .Nm diff Ns \'d is piped through .Xr pr 1 to paginate it; other differences are remembered and summarized after all text file differences are reported. .It Fl p With unified and context diffs, show with each change the first 40 characters of the last line before the context beginning with a letter, an underscore or a dollar sign. For C source code following standard layout conventions, this will show the prototype of the function the change applies to. .It Fl T Print a tab rather than a space before the rest of the line for the normal, context or unified output formats. This makes the alignment of tabs in the line consistent. .It Fl t Will expand tabs in output lines. Normal or .Fl c output adds character(s) to the front of each line which may screw up the indentation of the original source lines and make the output listing difficult to interpret. This option will preserve the original source's indentation. .It Fl w Is similar to .Fl b but causes whitespace (blanks and tabs) to be totally ignored. E.g., .Dq if (\ \&a == b \&) will compare equal to .Dq if(a==b) . .El .Pp Directory comparison options: .Bl -tag -width Ds .It Fl N If a file is found in only one directory, act as if it was found in the other directory too but was of zero size. .It Fl P If a file is found only in .Ar dir2 , act as if it was found in .Ar dir1 too but was of zero size. .It Fl r Causes application of .Nm recursively to common subdirectories encountered. .It Fl S Ar name Re-starts a directory .Nm in the middle, beginning with file .Ar name . .It Fl s Causes .Nm to report files which are the same, which are otherwise not mentioned. .It Fl X Ar file Exclude files and subdirectories from comparison whose basenames match lines in .Ar file . Multiple .Fl X options may be specified. .It Fl x Ar pattern Exclude files and subdirectories from comparison whose basenames match .Ar pattern . Patterns are matched using shell-style globbing via .Xr fnmatch 3 . Multiple .Fl x options may be specified. .El .Pp If both arguments are directories, .Nm sorts the contents of the directories by name, and then runs the regular file .Nm algorithm, producing a change list, on text files which are different. Binary files which differ, common subdirectories, and files which appear in only one directory are described as such. In directory mode only regular files and directories are compared. If a non-regular file such as a device special file or .Tn FIFO is encountered, a diagnostic message is printed. .Pp If only one of .Ar file1 and .Ar file2 is a directory, .Nm is applied to the non-directory file and the file contained in the directory file with a filename that is the same as the last component of the non-directory file. .Pp If either .Ar file1 or .Ar file2 is .Sq Fl , the standard input is used in its place. .Ss Output Style The default (without .Fl e , .Fl c , or .Fl n .\" -C options) output contains lines of these forms, where .Va XX , YY , ZZ , QQ are line numbers respective of file order. .Pp .Bl -tag -width "XX,YYcZZ,QQ" -compact .It Li XX Ns Ic a Ns Li YY At (the end of) line .Va XX of .Ar file1 , append the contents of line .Va YY of .Ar file2 to make them equal. .It Li XX Ns Ic a Ns Li YY,ZZ Same as above, but append the range of lines, .Va YY through .Va ZZ of .Ar file2 to line .Va XX of file1. .It Li XX Ns Ic d Ns Li YY At line .Va XX delete the line. The value .Va YY tells to which line the change would bring .Ar file1 in line with .Ar file1 . .It Li XX,YY Ns Ic d Ns Li ZZ Delete the range of lines .Va XX through .Va YY in .Ar file1 . .It Li XX Ns Ic c Ns Li YY Change the line .Va XX in .Ar file1 to the line .Va YY in .Ar file2 . .It Li XX,YY Ns Ic c Ns Li ZZ Replace the range of specified lines with the line .Va ZZ . .It Li XX,YY Ns Ic c Ns Li ZZ,QQ Replace the range .Va XX , Ns Va YY from .Ar file1 with the range .Va ZZ , Ns Va QQ from .Ar file2 . .El .Pp These lines resemble .Xr ed 1 subcommands to convert .Ar file1 into .Ar file2 . The line numbers before the action letters pertain to .Ar file1 ; those after pertain to .Ar file2 . Thus, by exchanging .Ic a for .Ic d and reading the line in reverse order, one can also determine how to convert .Ar file2 into .Ar file1 . As in .Xr ed 1 , identical pairs (where num1 = num2) are abbreviated as a single number. .Sh ENVIRONMENT .Bl -tag -width TMPDIR .It Ev TMPDIR If the environment variable .Ev TMPDIR exists, .Nm will use the directory specified by .Ev TMPDIR as the temporary directory. .El .Sh FILES .Bl -tag -width /tmp/diff.XXXXXXXX -compact .It Pa /tmp/diff. Ns Ar XXXXXXXX Temporary file used when comparing a device or the standard input. Note that the temporary file is unlinked as soon as it is created so it will not show up in a directory listing. .El .Sh DIAGNOSTICS The .Nm utility exits with one of the following values: .Pp .Bl -tag -width Ds -compact -offset indent .It 0 No differences were found. .It 1 Differences were found. .It \*(Gt1 An error occurred. .El .Sh SEE ALSO .Xr cmp 1 , .Xr comm 1 , .Xr diff3 1 , .Xr ed 1 , .Xr pr 1 , .Xr sdiff 1 , .Xr fnmatch 3 , .Xr re_format 7 .Sh STANDARDS The .Nm utility is expected to be a superset of the .St -p1003.1-2001 specification. .Sh HISTORY A .Nm command appeared in .At v6 . .Sh BUGS When comparing directories with the .Fl b , .Fl w or .Fl i options specified, .Nm first compares the files ala .Xr cmp 1 , and then decides to run the .Nm algorithm if they are not equal. This may cause a small amount of spurious output if the files then turn out to be identical because the only differences are insignificant whitespace or case differences.