Show differences among three files.
When two people have made independent changes to a common original, `diff3' can report the differences between the original and the two changed versions, and can produce a merged file that contains both persons' changes together with warnings about conflicts.
The files to compare are mine, older, and yours. At most one of these three file names can be -, which tells diff3 to read the standard input for that file.
Syntax diff3 [options] mine older yours Options -a Treat all files as text and compare them line-by-line, even if they do not appear to be text. -A Incorporate all changes from older to yours into mine, surrounding all conflicts with bracket lines. -e Generate an ed script that incorporates all the changes from older to yours into mine. -E Like -e, except bracket lines from overlapping changes' first and third files. With -e, an over- lapping change looks like this: <<<<<<< mine lines from mine ======= lines from yours >>>>>>> yours --ed Generate an ed script that incorporates all the changes from older to yours into mine. --easy-only Like -e, except output only the nonoverlapping changes. -i Generate w and q commands at the end of the ed script for System V compatibility. This option must be combined with one of the -AeExX3 options, and can not be combined with -m. --initial-tab Output a tab rather than two spaces before the text of a line in normal format. This causes the alignment of tabs in the line to look normal. -L label --label=label Use the label label for the brackets output by the -A, -E and -X options. This option can be given up to three times, one for each input file. The default labels are the names of the input files. Thus diff3 -L X -L Y -L Z -m A B C acts like diff3 -m A B C , except that the output looks like it came from files named X, Y and Z rather than from files named A, B and C. -m --merge Apply the edit script to the first file and send the result to standard output. Unlike piping the output from diff3 to ed, this works even for binary files and incomplete lines. -A is assumed if no edit script option is specified. --overlap-only Like -e, except output only the overlapping changes. --show-all Incorporate all unmerged changes from older to yours into mine, surrounding all overlapping changes with bracket lines. --show-overlap Like -e, except bracket lines from overlapping changes' first and third files. -T Output a tab rather than two spaces before the text of a line in normal format. This causes the align- ment of tabs in the line to look normal. --text Treat all files as text and compare them line-by- line, even if they do not appear to be text. -v --version Output the version number of diff3. -x Like -e, except output only the overlapping changes. -X Like -E, except output only the overlapping changes. In other words, like -x, except bracket changes as in -E. -3 Like -e, except output only the nonoverlapping changes.
Multiple single letter options (unless they take an argument) can be combined into a single command line argument.
`diff3' normally compares three input files line by line, finds groups of lines that differ, and reports each group of differing lines. Its output is designed to make it easy to inspect two different sets of changes to the same file.
An exit status of 0 means diff3 was successful, 1 means some conflicts were found, and 2 means trouble.
“One person can make a difference and every person must try” ~ John F. Kennedy
diff3 man page - Apple.com
cmp - Compare two files
comm - Compare two sorted files line by line
diff - Display the differences between two files
sdiff - merge two files interactively