1diff(1) User Commands diff(1)
2
6 diff - compare two files
7
9 diff [-bitw] [-c | -e | -f | -h | -n | -u] file1 file2
10 diff [-bitw] [-C number | -U number] file1 file2
13 diff [-bitw] [-D string] file1 file2
16 diff [-bitw] [-c | -e | -f | -h | -n | -u] [-l] [-r] [-s]
19 [-S name] directory1 directory2
20
23 The diff utility will compare the contents of file1 and file2 and write
24 to standard output a list of changes necessary to convert file1 into
25 file2. This list should be minimal. Except in rare circumstances, diff
26 finds a smallest sufficient set of file differences. No output will be
27 produced if the files are identical.
28 The normal output contains lines of these forms:
31 n1 a n3,n4
33 n1,n2 d n3
34 n1,n2 c n3,n4
35 where n1 and n2 represent lines file1 and n3 and n4 represent lines in
40 file2 These lines resemble ed(1) commands to convert file1 to file2. By
41 exchanging a for d and reading backward, file2 can be converted to
42 file1. As in ed, identical pairs, where n1=n2 or n3=n4, are abbreviated
43 as a single number.
44 Following each of these lines come all the lines that are affected in
47 the first file flagged by `<', then all the lines that are affected in
48 the second file flagged by `>'.
49
51 The following options are supported:
52 -b Ignores trailing blanks (spaces and tabs) and treats other
54 strings of blanks as equivalent.
55 -i Ignores the case of letters. For example, `A' will compare equal
58 to `a'.
59 -t Expands TAB characters in output lines. Normal or -c output adds
62 character(s) to the front of each line that may adversely affect
63 the indentation of the original source lines and make the output
64 lines difficult to interpret. This option will preserve the
65 original source's indentation.
66 -w Ignores all blanks (SPACE and TAB characters) and treats all
69 other strings of blanks as equivalent. For example, `if ( a == b
70 )' will compare equal to `if(a==b)'.
71 The following options are mutually exclusive:
75 -c Produces a listing of differences with three lines of
77 context. With this option, output format is modified
78 slightly. That is, output begins with identification of
79 the files involved and their creation dates, then each
80 change is separated by a line with a dozen *'s. The lines
81 removed from file1 are marked with '—'. The lines added
82 to file2 are marked '+'. Lines that are changed from one
83 file to the other are marked in both files with '!'.
84 -C number Produces a listing of differences identical to that pro‐
87 duced by -c with number lines of context.
88 -D string Creates a merged version of file1 and file2 with C pre‐
91 processor controls included so that a compilation of the
92 result without defining string is equivalent to compiling
93 file1, while defining string will yield file2.
94 -e Produces a script of only a, c, and d commands for the
97 editor ed, which will recreate file2 from file1. In con‐
98 nection with the -e option, the following shell program
99 may help maintain multiple versions of a file. Only an
100 ancestral file ($1) and a chain of version-to-version ed
101 scripts ($2,$3,...) made by diff need be on hand. A
102 ``latest version'' appears on the standard output.
103 (shift; cat $*; echo a´1,$p') | ed − $1
105 -f Produces a similar script, not useful with ed, in the
110 opposite order.
111 -h Does a fast, half-hearted job. It works only when changed
114 stretches are short and well separated, but does work on
115 files of unlimited length. Options -c, -C, -D, -e, -f, and
116 -n are unavailable with -h. diff does not descend into
117 directories with this option.
118 -n Produces a script similar to -e, but in the opposite order
121 and with a count of changed lines on each insert or delete
122 command.
123 -u Produces a listing of differences with three lines of con‐
126 text. The output is similar to that of the -c option,
127 except that the context is "unified". Removed and changed
128 lines in file1 are marked by a '-' while lines added or
129 changed in file2 are marked by a '+'. Both versions of
130 changed lines appear in the output, while added, removed,
131 and context lines appear only once. The identification of
132 file1 and file2 is different, with "−−−" and "+++" being
133 printed where "***" and "−−−" would appear with the -c
134 option. Each change is separated by a line of the form
135 @@ -n1,n2 +n3,n4 @@
137 -U number Produces a listing of differences identical to that pro‐
142 duced by -u with number lines of context.
143 The following options are used for comparing directories:
147 -l Produces output in long format. Before the diff, each text
149 file is piped through pr(1) to paginate it. Other differ‐
150 ences are remembered and summarized after all text file
151 differences are reported.
152 -r Applies diff recursively to common subdirectories encoun‐
155 tered.
156 -s Reports files that are identical. These identical files
159 would not otherwise be mentioned.
160 -S name Starts a directory diff in the middle, beginning with the
163 file name.
164
167 The following operands are supported:
168 file1 A path name of a file or directory to be compared. If
170 file2 either file1 or file2 is −, the standard input will be
171 used in its place.
172 directory1 A path name of a directory to be compared.
175 directory2
176 If only one of file1 and file2 is a directory, diff will be applied to
179 the non-directory file and the file contained in the directory file
180 with a filename that is the same as the last component of the non-
181 directory file.
182
184 See largefile(5) for the description of the behavior of diff when
185 encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
186
188 Example 1 Typical output of the diff command
189 In the following command, dir1 is a directory containing a directory
192 named x, dir2 is a directory containing a directory named x, dir1/x and
193 dir2/x both contain files named date.out, and dir2/x contains a file
194 named y:
195 example% diff -r dir1 dir2
198 Common subdirectories: dir1/x and dir2/x
199 Only in dir2/x: y
201 diff -r dir1/x/date.out dir2/x/date.out
203 1c1
205 < Mon Jul 2 13:12:16 PDT 1990
207 ---
209 > Tue Jun 19 21:41:39 PDT 1990
211
215 See environ(5) for descriptions of the following environment variables
216 that affect the execution of diff: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES,
217 LC_TIME, and NLSPATH.
218 TZ Determines the locale for affecting the timezone used for calcu‐
220 lating file timestamps written with the -C and -c options.
221
224 The following exit values are returned:
225 0 No differences were found.
227 1 Differences were found.
230 >1 An error occurred.
233
236 /tmp/d????? temporary file used for comparison
237 /usr/lib/diffh executable file for -h option
240
243 See attributes(5) for descriptions of the following attributes:
244 ┌─────────────────────────────┬─────────────────────────────┐
249 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
250 ├─────────────────────────────┼─────────────────────────────┤
251 │Availability │SUNWesu │
252 ├─────────────────────────────┼─────────────────────────────┤
253 │CSI │Enabled │
254 ├─────────────────────────────┼─────────────────────────────┤
255 │Interface Stability │Standard │
256 └─────────────────────────────┴─────────────────────────────┘
257
259 bdiff(1), cmp(1), comm(1), dircmp(1), ed(1), pr(1), sdiff(1),
260 attributes(5), environ(5), largefile(5), standards(5)
261
263 Editing scripts produced under the -e or -f options are naive about
264 creating lines consisting of a single period (.).
265 Missing NEWLINE at end of file indicates that the last line of the file
268 in question did not have a NEWLINE. If the lines are different, they
269 will be flagged and output, although the output will seem to indicate
270 they are the same.
271SunOS 5.11 22 Sep 2004 diff(1)