as

Additional Notes

as is the GNU assembler. It converts assembly source into object files that can later be linked into executables or libraries.

Most developers invoke it indirectly through compilers such as gcc or clang, but direct use is useful when learning assembly, working with low-level code, or debugging build toolchains.

Syntax

as [options] source.s -o output.o

Parameters

• source.s: Assembly source file.
• output.o: Object file to create.
• options: Architecture, debug, listing, and output controls.

Common Options

• -o FILE: Write output object file.
• -g: Generate debug information.
• -a: Produce an assembly listing.
• --version: Show version information.
• --help: Show supported target-specific options.

Examples

as hello.s -o hello.o

Assemble one source file.

ld hello.o -o hello

Link an object file manually.

gcc -c hello.s -o hello.o

Use the compiler driver as an easier frontend.

Practical Notes

• Assembly syntax and options depend on architecture.
• Use gcc or clang as the driver when you need include paths, startup files, or normal linking behavior.
• Inspect object files with objdump, readelf, or nm.