16. Invoking 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.

sdiff without ‘-o’ (or ‘--output’) produces a side-by-side difference. This usage is obsolete; use the ‘-y’ or ‘--side-by-side’ option of diff instead.

An exit status of 0 means no differences were found, 1 means some differences were found, and 2 means trouble.