diff(1) 							   User Commands							   diff(1)

NAME

       diff - compare two files

SYNOPSIS

       diff [-bitw] [-c | -e | -f | -h | -n | -u] file1 file2

       diff [-bitw] [-C number | -U number] file1 file2

       diff [-bitw] [-D string] file1 file2

       diff [-bitw] [-c | -e | -f | -h | -n | -u] [-l] [-r] [-s]
	    [-S name] directory1 directory2

DESCRIPTION

       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:

	 n1 a n3,n4
	 n1,n2 d n3
	 n1,n2 c n3,n4

       where n1 and n2 represent lines 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 backward, file2 can be converted to file1. As in ed, identical pairs, where n1=n2 or n3=n4, are  abbrevi-
       ated 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'.

       -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 origi-
	      nal 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 *'s. 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, 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, 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	      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
       file2	      place.

       directory1     A path name of a directory to be compared.
       directory2

       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(5) for the description of the behavior of diff when encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).

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(5) for descriptions of the following environment variables that affect the execution of diff: LANG, LC_ALL,	LC_CTYPE,  LC_MES-
       SAGES, LC_TIME, and NLSPATH.

       TZ     Determines the locale for affecting the timezone used for calculating file timestamps written with the -C and -c options.

EXIT STATUS

       The following exit values are returned:

       0      No differences were found.

       1      Differences were found.

       >1     An error occurred.

FILES

       /tmp/d?????	  temporary file used for comparison

       /usr/lib/diffh	  executable file for -h option

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWesu			   |
       +-----------------------------+-----------------------------+
       |CSI			     |Enabled			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       bdiff(1), cmp(1), comm(1), dircmp(1), ed(1), pr(1), sdiff(1), attributes(5), environ(5), largefile(5), standards(5)

NOTES

       Editing scripts produced under the -e or -f options are naive about creating lines consisting of a single period (.).

       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.

SunOS 5.11							    22 Sep 2004 							   diff(1)