The yasm command assembles the file infile and directs output to the file outfile if specified. If outfile is not specified, yasm will derive a default output file name from the name of its input file, usually by appending .o or .obj, or by removing all extensions for a raw binary file. Failing that, the output file name will be yasm.out.

If called with an infile of “-”, yasm assembles the standard input and directs output to the file outfile, or yasm.out if no outfile is specified.

If errors or warnings are discovered during execution, Yasm outputs the error message to stderr (usually the terminal). If no errors or warnings are encountered, Yasm does not output any messages.