usage: ghdl COMMAND [OPTIONS] ...
COMMAND is one of:
-a [OPTS] FILEs    Analyze FILEs
-e [OPTS] UNIT [ARCH]  Elaborate UNIT
-r,--elab-run [OPTS] UNIT [ARCH] [RUNOPTS]  Run UNIT
-c [OPTS] FILEs -r UNIT [ARCH] [RUNOPTS]  Compile, elaborate and run UNIT
-m [OPTS] UNIT [ARCH]  Make UNIT
--gen-makefile [OPTS] UNIT [ARCH]  Generate a Makefile for UNIT
--dispconfig       Disp tools path
--run-help         Disp help for RUNOPTS options
-i [OPTS] FILEs    Import units of FILEs
-s [OPTS] FILEs    Check syntax of FILEs
-d or --dir        Disp contents of the work library
-f FILEs           Disp units in FILES
--clean            Remove generated files
--remove           Remove generated files and library file
--disp-standard    Disp std.standard in pseudo-vhdl
--chop [OPTS] FILEs  Chop FILEs
--lines FILEs      Precede line with its number
--pp-html FILEs    Pretty-print FILEs in HTML
--xref-html FILEs  Display FILEs in HTML with xrefs
--xref FILEs  Generate xrefs
-h or --help [CMD] Disp this help or [help on CMD]
-v or --version    Disp ghdl version
--options-help     Disp help for analyzer options

--options-help for analyzer options.
Main options:
  --work=LIB         use LIB as work library
  --workdir=DIR      use DIR for the file library
  -PPATH             add PATH in the library path list
  --std=87           select vhdl 87 standard
  --std=93           select vhdl 93 standard
  --std=93c          select vhdl 93 standard and allow 87 syntax (default)
  --ieee=synopsys    select more libraries such as std_logic_textio and std_logic_arith
  --[no-]vital-checks  do [not] check VITAL restrictions
Warnings:
  --warn-binding     warns for component not bound
  --warn-reserved    warns use of 93 reserved words in vhdl87
  --warn-library     warns for redefinition of a design unit
  --warn-vital-generic  warns of non-vital generic names
  --warn-delayed-checks warns for checks performed at elaboration
  --warn-body        warns for not necessary package body
  --warn-specs       warns if a all/others spec does not apply
  --warn-unused      warns if a subprogram is never used
  --warn-error       turns warnings into errors
Illegal extensions:
  -fexplicit         give priority to explicitly declared operator
  -C  --mb-comments  allow multi-bytes chars in a comment
  --bootstrap        allow --work=std
  --syn-binding      use synthesis default binding rule
Compilation dump:
  -dp                dump tree after parsing
  -ds                dump tree after semantics
  -da                dump tree after annotate
  --dall             -dX options apply to all files
Compilation list:
  -ls                after semantics
  -lc                after canon
  -la                after annotation
  --lall             -lX options apply to all files
  -lv                verbose list
  -v                 disp compilation stages