This appendix describes how to invoke the assembler from the command line, and details the command-line options.
You invoke the assembler command line as follows:
as [options] [inputfile] ...
The as command translates the assembly language source files, inputfile, into an executable object file, objfile. The assembler recognizes the filename argument hyphen (-) as the standard input. It accepts more than one file name on the command line. The input file is the concatenation of all the specified files. If an invalid option is given or the command line contains a syntax error, the assembler prints the error (including a synopsis of the command line syntax and options) to standard error output, and then terminates.
The assembler supports macros, #include files, and symbolic substitution through use of the C preprocessor cpp(1). The assembler invokes the preprocessor before assembly begins if it has been specified from the command line as an option. (See the -P option.)