diff - GNU diff, diff3, sdiff, and cmp utilities - version 2.8.1

This version of diff provides all the features of BSD's diff.
It has many additional features, including:

        ignore changes that just insert or delete blank lines.

	in context format, for each unit of differences, show some of
	the last preceding line that matches the specified regexp.

        heuristics for fast handling of large files with many scattered
        small changes.

	ignore changes that just insert or delete lines that
	match the specified regexp.

        compare of entire directories

   	print a tab rather than a space before the text of a line
	in normal or context format.  This causes the alignment
	of tabs in the line to look normal.

	produce unified style output with # context lines (default 3).
	This style is like -c, but it is more compact because context
	lines are printed only once.  Lines from just the first file
	are marked '-'; lines from just the second file are marked '+'.

	side-by-side output

This version of diff3 has all of BSD diff3's features, with additional
features.

sdiff is used to merge two files interactively.

cmp is used to  show the offsets and line numbers where two files differ.
cmp can also show all the characters that differ between the two files,
side by side.