diff --git a/exe/vaporware b/exe/vaporware
index 1d00e94..6196846 100755
--- a/exe/vaporware
+++ b/exe/vaporware
@@ -3,21 +3,84 @@
 require "vaporware"
 require "optparse"
 opt = OptionParser.new
-options = {}
-opt.on("-c", "--compiler[=VAL]", "this option is selecting compiler precompiled file, default: \"self\"") { |v| options[:compiler] = v }
-opt.on("-a", "--assembler[=VAL]", "this option is selecting assembler assembler file, default: \"as\"") { |v| options[:assembler] = v }
-opt.on("-D", "--debug") { |v| options[:debug] = v }
-opt.on("-o", "--objects[=VAL]") { |v| options[:dest] = v }
-opt.on("--compiler-options[=VAL]", "compiler options") { |v| options[:compiler_options] = v.split(",") }
-opt.on("-s", "--shared-library") { |v| options[:shared] = v }
-opt.on("-l", "--linker[=VAL]", "selecting linker: gold, lld, and mold, default: \"gold\".") { |v| options[:linker] = v }
+options = {
+  compile: true,
+  assemble: true,
+  link: true,
+}
+
+subcommands = Hash.new do |hash, key|
+  $stderr.puts "no such subcommand: #{key}"
+  exit 1
+end
+
+subcommands["compile"] = OptionParser.new do |opt|
+  opt.on("-o", "--output=FILE", "Output file name") { |v| options[:output] = v }
+  opt.on("-c", "--assemble-only", "Assembly only, do not link") { options[:link] = false }
+  opt.on("-S", "--compile-only", "Compile only, do not assemble") do
+    options[:assemble] = false
+    options[:link] = false
+  end
+  opt.on("-a", "--assembler=ASSEMBLER", "Specify the assembler to use (e.g., as, gas)") { |v| options[:assembler] = v }
+  opt.on("-l", "--linker=LINKER", "Specify the linker to use (e.g., gold, lld, mold)") { |v| options[:linker] = v }
+
+  opt.on("-s", "--shared", "Compile as shared object") { options[:shared] = true }
+  opt.on("-d", "--debug", "Compile with debug information") { options[:debug] = true }
+end
+
+subcommands["assemble"] = OptionParser.new do |opt|
+  opt.on("-o", "--output=FILE", "Output file name") { |v| options[:output] = v }
+  opt.on("-a", "--assembler=ASSEMBLER", "Specify the assembler to use (e.g., as, gas)") { |v| options[:assembler] = v }
+  opt.on("-c", "--assemble-only", "Assemble only, do not link") { options[:link] = false }
+
+  opt.on("-s", "--shared", "Compile as shared object") { options[:shared] = true }
+  opt.on("-d", "--debug", "Compile with debug information") { options[:debug] = true }
+end
+
+subcommands["link"] = OptionParser.new do |opt|
+  opt.on("-o", "--output=FILE", "Output file name") { |v| options[:output] = v }
+  opt.on("-l", "--linker=LINKER", "Specify the linker to use (e.g., gold, lld, mold)") { |v| options[:linker] = v }
+
+  opt.on("-s", "--shared", "Compile as shared object") { options[:shared] = true }
+  opt.on("-d", "--debug", "Compile with debug information") { options[:debug] = true }
+end
 
 begin
-  opt.parse!(ARGV)
+  subcommands[ARGV.shift].parse!(ARGV) if ARGV.any?
   raise "please compile target file" if ARGV.empty?
 rescue => e
   STDERR.puts(e.message)
   exit 1
 end
 
-Vaporware::Compiler.compile!(input: ARGV.shift, **options)
+assembler, linker = nil, nil
+assembler = options[:assembler] || "self" 
+linker = options[:linker] || "mold"
+debug = options[:debug] || false
+output = options[:output] || "a.out"
+input = ARGV.first
+shared = options[:shared] || false
+
+if File.extname(input) == ".s"
+  options[:assemble] = true
+  options[:compile] = false
+end
+
+basename = File.expand_path(File.basename(input, ".*"))
+extname = File.extname(output) == ".so"
+
+output = basename + ".s"
+Vaporware.compile(input:, output:, debug:) if options[:compile]
+input, output = output, basename + ".o"
+if options[:assemble]
+  input = ARGV.first unless options[:compile]
+  Vaporware.assemble(input:, output:, assembler:, debug:)
+  File.delete(input) if File.exist?(input) && !debug && File.extname(input) != ".s"
+end
+if options[:link]
+  input, output = output, basename
+  output = options[:output] || output
+  output += ".so" if options[:shared] && !extname
+  Vaporware.link(input:, output:, debug:, shared:, linker:) if options[:link]
+  File.delete(input) if File.exist?(input) && !debug && File.extname(input) != ".o"
+end
diff --git a/lib/vaporware.rb b/lib/vaporware.rb
index 20ab3b5..b41dc85 100644
--- a/lib/vaporware.rb
+++ b/lib/vaporware.rb
@@ -12,8 +12,17 @@ def compile!(input:, assembler: "as", linker: "ld", output: "tmp", debug: false,
     d = File.expand_path(output)
     basename = "#{File.dirname(d)}/#{File.basename(d, ".*")}"
     execf = "#{basename}#{File.extname(d)}"
-    compiler = Vaporware::Compiler.compile!(input:, output: basename + ".s", debug:, compiler_options:, shared:)
-    assembler = Vaporware::Assembler.assemble!(input: basename+".s", output: basename+".o", assembler:, debug:)
-    linker = Vaporware::Linker.link!(input: basename+".o", output: execf, linker:, debug:, shared:)
+    compile(input:, output: basename+".s", debug:, shared:)
+    assemble(input: basename+".s", output: basename+".o", assembler:, debug:, shared:)
+    link(input: basename+".o", output: execf, linker:, debug:, shared:)
+  end
+  def compile(input:, output: "tmp.s", debug: false, shared: false)
+    Vaporware::Compiler.compile!(input:, output:, debug:)
+  end
+  def assemble(input:, output: "tmp.o", debug: false, shared: false, assembler: "as")
+    Vaporware::Assembler.assemble!(input:, output:, debug:, assembler:, shared:)
+  end
+  def link(input:, output: "tmp", linker: "ld", debug: false, shared: false)
+    Vaporware::Linker.link!(input:, output:, linker:, debug:, shared:)
   end
 end
diff --git a/lib/vaporware/assembler.rb b/lib/vaporware/assembler.rb
index a459d9c..f3e185a 100644
--- a/lib/vaporware/assembler.rb
+++ b/lib/vaporware/assembler.rb
@@ -6,12 +6,12 @@
 require_relative "assembler/elf/section_header"
 
 class Vaporware::Assembler
-  GCC_ASSEMBLERS = ["gcc", "as"]
-  CLANG_ASSEMBLERS = ["clang", "llvm"]
-  ASSEMBLERS = GCC_ASSEMBLERS + CLANG_ASSEMBLERS
+  GCC_ASSEMBLERS = ["gcc", "as"].freeze
+  CLANG_ASSEMBLERS = ["clang", "llvm"].freeze
+  ASSEMBLERS = (GCC_ASSEMBLERS + CLANG_ASSEMBLERS).freeze
   class Error < StandardError; end
 
-  def self.assemble!(input:, output: File.basename(input, ".*") + ".o", assembler: "as", debug: false) = new(input:, output:, assembler:, debug:).assemble
+  def self.assemble!(input:, output: File.basename(input, ".*") + ".o", assembler: "as", debug: false, shared:false) = new(input:, output:, assembler:, debug:).assemble
 
   def initialize(input:, output: File.basename(input, ".*") + ".o", assembler: "as", type: :relocatable, debug: false)
     @input, @output = input, output
@@ -20,7 +20,7 @@ def initialize(input:, output: File.basename(input, ".*") + ".o", assembler: "as
     @debug = debug
   end
 
-  def assemble(assembler: @assembler, assembler_options: [], input: @input, output: @output, debug: false)
+  def assemble(assembler: @assembler, assembler_options: [], input: @input, output: @output, debug: false, shared: false)
     if ASSEMBLERS.include?(assembler)
       IO.popen([command(assembler), *assembler_options, "-o", output, input].join(" ")).close
     else
diff --git a/sample/assembler/else.s b/sample/assembler/else.s
index 47334f6..cde0d8e 100644
--- a/sample/assembler/else.s
+++ b/sample/assembler/else.s
@@ -13,7 +13,6 @@ main:
   pop rax
   mov rsp, rbp
   pop rbp
-  ret
   jmp .Lend0
 .Lelse0:
   push 2