diff(1) [v7 man page]
DIFF(1) General Commands Manual DIFF(1) NAME
diff - differential file comparator SYNOPSIS
diff [ -efbh ] file1 file2 DESCRIPTION
Diff tells what lines must be changed in two files to bring them into agreement. If file1 (file2) is `-', the standard input is used. If file1 (file2) is a directory, then a file in that directory whose file-name is the same as the file-name of file2 (file1) is used. The normal output contains lines of these forms: n1 a n3,n4 n1,n2 d n3 n1,n2 c n3,n4 These lines resemble ed commands to convert file1 into file2. The numbers after the letters pertain to file2. In fact, by exchanging `a' for `d' and reading backward one may ascertain equally how to convert file2 into file1. As in ed, 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 `>'. The -b option causes trailing blanks (spaces and tabs) to be ignored and other strings of blanks to compare equal. The -e option produces a script of a, c and d commands for the editor ed, which will recreate file2 from file1. The -f option produces a similar script, not useful with ed, in the opposite order. In connection with -e, 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 $*; echo '1,$p') | ed - $1 Except in rare circumstances, diff finds a smallest sufficient set of file differences. Option -h does a fast, half-hearted job. It works only when changed stretches are short and well separated, but does work on files of unlimited length. Options -e and -f are unavailable with -h. FILES
/tmp/d????? /usr/lib/diffh for -h SEE ALSO
cmp(1), comm(1), ed(1) DIAGNOSTICS
Exit status is 0 for no differences, 1 for some, 2 for trouble. BUGS
Editing scripts produced under the -e or -f option are naive about creating lines consisting of a single `.'. DIFF(1)
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DIFF3(1) General Commands Manual DIFF3(1) NAME
diff3 - 3-way differential file comparison SYNOPSIS
diff3 [ -exEX3 ] file1 file2 file3 DESCRIPTION
Diff3 compares three versions of a file, and publishes disagreeing ranges of text flagged with these codes: ==== all three files differ ====1 file1 is different ====2 file2 is different ====3 file3 is different The type of change suffered in converting a given range of a given file to some other is indicated in one of these ways: f : n1 a Text is to be appended after line number n1 in file f, where f = 1, 2, or 3. f : n1 , n2 c Text is to be changed in the range line n1 to line n2. If n1 = n2, the range may be abbreviated to n1. The original contents of the range follows immediately after a c indication. When the contents of two files are identical, the contents of the lower-numbered file is suppressed. Under the -e option, diff3 publishes a script for the editor ed that will incorporate into file1 all changes between file2 and file3, i.e. the changes that normally would be flagged ==== and ====3. Option -x (-3) produces a script to incorporate only changes flagged ==== (====3). The following command will apply the resulting script to `file1'. (cat script; echo '1,$p') | ed - file1 The -E and -X are similar to -e and -x, respectively, but treat overlapping changes (i.e., changes that would be flagged with ==== in the normal listing) differently. The overlapping lines from both files will be inserted by the edit script, bracketed by "<<<<<<" and ">>>>>>" lines. For example, suppose lines 7-8 are changed in both file1 and file2. Applying the edit script generated by the command "diff3 -E file1 file2 file3" to file1 results in the file: lines 1-6 of file1 <<<<<<< file1 lines 7-8 of file1 ======= lines 7-8 of file3 >>>>>>> file3 rest of file1 The -E option is used by RCS merge(1) to insure that overlapping changes in the merged files are preserved and brought to someone's atten- tion. FILES
/tmp/d3????? /usr/libexec/diff3 SEE ALSO
diff(1) BUGS
Text lines that consist of a single `.' will defeat -e. 7th Edition October 21, 1996 DIFF3(1)