sdiff
The sdiff command merges two files and interactively outputs the
results. Its arguments are as follows:
sdiff -o outfile options... from-file to-file
This merges from-file with to-file, with output to outfile.
If from-file is a directory and to-file is not, sdiff
compares the file in from-file whose file name is that of to-file,
and vice versa. from-file and to-file may not both be
directories.
sdiff options begin with `-', so normally from-file
and to-file may not begin with `-'. However, `--' as an
argument by itself treats the remaining arguments as file names even if
they begin with `-'. You may not use `-' as an input file.
An exit status of 0 means no differences were found, 1 means some differences were found, and 2 means trouble.
sdiff without `-o' (or `--output') produces a
side-by-side difference. This usage is obsolete; use `diff
--side-by-side' instead.
diff.