diff [-l/r/s] [-c/e/f/h] [-b] dir1 dir2
diff [-c/e/f/h] [-b] file1 file2
diff [-D<str>] [-b] file1 file2

Differential file and dir comparator.
c/e/f/h/D switches are mutually exclusive.

Dir switches -
l	- Long output format.
r	- Recursive to common sub-directories.
s	- Report files which are the same.
S	- Start with <file>.

File switches -
b	- ignore trailing blanks & make all blank strings equivalent.
e	- Produce ed script.
f	- Produce non-ed script.
c	- Define # lines of context and/or label differences.
h	- Half-hearted job.
D	- Create a merged version on stdout.

See also - uniq, cmp, comm.
