DIFF(1) User Commands DIFF(1)
NAME
diff - compare two files
SYNOPSIS
diff [
-biqtw] [
-c |
-e |
-f |
-h |
-n |
-u]
file1 file2 diff [
-biqtw] [
-C number |
-U number]
file1 file2 diff [
-biqtw] [
-D string]
file1 file2 diff [
-biqtw] [
-c |
-e |
-f |
-h |
-n |
-u] [
-l] [
-r] [
-s] [
-S name]
directory1 directory2DESCRIPTION
The
diff utility will compare the contents of
file1 and
file2 and write to
standard output a list of changes necessary to convert
file1 into
file2.
This list should be minimal. Except in rare circumstances,
diff finds a
smallest sufficient set of file differences. No output will be produced if
the files are identical.
The normal output contains lines of these forms:
n1an3,
n4 n1,
n2dn3 n1,
n2cn3,
n4 where
n1 and
n2 represent lines in
file1 and
n3 and
n4 represent lines in
file2 These lines resemble
ed(1) commands to convert
file1 to
file2. By
exchanging
a for
d and reading backwards,
file2 can be converted to
file1.
As in
ed(1), identical pairs, where
n1=
n2 or
n3=
n4 are abbreviated as a
single number.
Following each of these lines come all the lines that are affected in the
first file flagged by `<', then all the lines that are affected in the
second file flagged by `>'.
OPTIONS
The following options are supported:
-b Ignores trailing blanks (spaces and tabs) and treats other strings
of blanks as equivalent.
-i Ignores the case of letters. For example, ` `A' will compare equal
to `a'.
-q report only when files differ
-t Expands TAB characters in output lines. Normal or
-c output adds
character(s) to the front of each line that may adversely affect
the indentation of the original source lines and make the output
lines difficult to interpret. This option will preserve the
original source's indentation.
-w Ignores all blanks (SPACE and TAB characters) and treats all other
strings of blanks as equivalent. For example, `if (a == b') will
compare equal to `if (a==b)'.
The following options are mutually exclusive:
-c Produces a listing of differences with three lines of context.
With this option, output format is modified slightly. That is,
output begins with identification of the files involved and their
creation dates, then each change is separated by a line with a
dozen asterisks (*). The lines removed from
file1 are marked with
`--'. The lines added to
file2 are marked `+'. Lines that are
changed from one file to the other are marked in both files with
`!'.
-C number Produces a listing of differences identical to that produced by
-c with
number lines of context.
-D string Creates a merged version of
file1 and
file2 with C preprocessor
controls included so that a compilation of the result without
defining
string is equivalent to compiling
file1, while defining
string will yield
file2.
-e Produces a script of only
a,
c, and
d commands for the editor
ed(1), which will recreate
file2 from
file1. In connection with
the
-e option, the following shell program may help maintain
multiple versions of a file. Only an ancestral file ($1) and a
chain of version-to-version
ed scripts ($2,$3,...) made by
diff need be on hand. A "latest version" appears on the standard
output.
(shift; cat $*; echo a'1,$p') | ed - $1
-f Produces a similar script, not useful with
ed(1), in the opposite
order.
-h Does a fast, half-hearted job. It works only when changed
stretches are short and well separated, but does work on files of
unlimited length. Options
-c,
-C,
-D,
-e,
-f, and
-n are
unavailable with
-h.
diff does not descend into directories with
this option.
-n Produces a script similar to
-e, but in the opposite order and with
a count of changed lines on each insert or delete command.
-u Produces a listing of differences with three lines of context. The
output is similar to that of the
-c option, except that the context
is "unified". Removed and changed lines in
file1 are marked by a
`-' while lines added or changed in
file2 are marked by a `+'.
Both versions of changed lines appear in the output, while added,
removed, and context lines appear only once. The identification of
file1 and
file2 is different, with "---" and "+++" being printed
where "***" and "---" would appear with the
-c option. Each change
is separated by a line of the form
@@ -n1,
n2 +n3,
n4 @@ -U number Produces a listing of differences identical to that produced by
-u with
number lines of context.
The following options are used for comparing directories:
-l Produces output in long format. Before the
diff, each text file is
piped through
pr(1) to paginate it. Other differences are
remembered and summarized after all text file differences are
reported.
-r Applies
diff recursively to common subdirectories encountered.
-s Reports files that are identical. These identical files would not
otherwise be mentioned.
-S name Starts a directory
diff in the middle, beginning with the file
name.
OPERANDS
The following operands are supported:
file1 file2 A path name of a file or directory to be compared. If
either
file1 or
file2 is `-', the standard input will be
used in its place.
directory1 directory2 A path name of a directory to be compared.
If only one of
file1 and
file2 is a directory,
diff will be 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.
USAGE
See
largefile(7) for the description of the behavior of
diff when
encountering files greater than or equal to 2 Gbyte (2^31 bytes).
FILES
/tmp/d????? temporary file used for comparison
/usr/lib/diffh executable file for
-h option
EXIT STATUS
The following exit values are returned:
0 No differences were found.
1 Differences were found.
>1 An error occurred.
EXAMPLES
Example 1 Typical output of the diff command
In the following command,
dir1 is a directory containing a directory named
x,
dir2 is a directory containing a directory named
x,
dir1/x and
dir2/x both contain files named
date.out, and
dir2/x contains a file named
y:
example% diff -r dir1 dir2
Common subdirectories: dir1/x and dir2/x
Only in dir2/x: y
diff -r dir1/x/date.out dir2/x/date.out
1c1
< Mon Jul 2 13:12:16 PDT 1990
---
> Tue Jun 19 21:41:39 PDT 1990
ENVIRONMENT VARIABLES
See
environ(7) for descriptions of the following environment variables that
affect the execution of
diff: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, LC_TIME,
and NLSPATH.
TZ Determines the locale for affecting the timezone used for
calculating file timestamps written with the
-C and
-c options.
INTERFACE STABILITY
The command line interface of
diff is
Committed. The output of
diff is
Committed.
SEE ALSO
bdiff(1),
cmp(1),
comm(1),
dircmp(1),
ed(1),
pr(1),
sdiff(1),
attributes(7),
environ(7),
largefile(7),
standards(7)NOTES
Editing scripts produced under the
-e or
-f options are na"ive about
creating lines consisting of a single dot `.'.
Missing NEWLINE at end of file indicates that the last line of the file in
question did not have a NEWLINE. If the lines are different, they will be
flagged and output, although the output will seem to indicate they are the
same.
OmniOS February 23, 2022 OmniOS