mono [options] file [arguments...]

The runtime contains a native code generator that transforms the Common Intermediate Language into native code.

The code generator can operate in two modes: just in time compilation (JIT) or ahead of time compilation (AOT). Since code can be dynamically loaded, the runtime environment and the JIT are always present, even if code is compiled ahead of time.

The runtime loads ths specified file and optionally passes the arguments to it. The file is an ECMA assembly. They typically have a .exe or .dll extension.

The runtime provides a number of configuration options for running applications, for developping and debugging, and for testing and debugging the runtime itself.

--aot

This option is used to precompile the CIL code in the specified assembly to native code. The generated code is stored in a file with the extension .so. This file will be automatically picked up by the runtime when the assembly is executed.

Ahead-of-Time compilation is most useful if you use it in combination with the -O=all,-shared flag which enables all of the optimizations in the code generator to be performed. Some of those optimizations are not practical for Just-in-Time compilation since they might be very time consuming.

Unlike the .NET Framework, Ahead-of-Time compilation will not generate domain independent code: it generates the same code that the Just-in-Time compiler would produce. Since most applications use a single domain, this is fine. If you want to optimize the generated code for use in multi-domain applications, consider using the -O=shared flag.

This pre-compiles the methods, but the original assembly is still required to execute as this one contains the metadata and exception information which is not availble on the generated file. When precompiling code, you might want to compile with all optimizations (-O=all). Pre-compiled code is position independent code.

Pre compilation is just a mechanism to reduce startup time, and avoid just-in-time compilation costs. The original assembly must still be present, as the metadata is contained there.

--config filename

Load the specified configuration file instead of the default one(s). The default files are /etc/mono/config and ~/.mono/config or the file specified in the MONO_CONFIG environment variable, if set. See the mono-config(5) man page for details on the format of this file.

--help, -h

Displays usage instructions.

--optimize=MODE, -O=mode

MODE is a comma separated list of optimizations. They also allow optimizations to be turned off by prefixing the optimization name with a minus sign.

The following optimizations are implemented:

             all        Turn on all optimizations
             peephole   Peephole postpass
             branch     Branch optimizations
             inline     Inline method calls
             cfold      Constant folding
             consprop   Constant propagation
             copyprop   Copy propagation
             deadce     Dead code elimination
             linears    Linear scan global reg allocation
             cmov       Conditional moves
             shared     Emit per-domain code
             sched      Instruction scheduling
             intrins    Intrinsic method implementations
             tailc      Tail recursion and tail calls
             loop       Loop related optimizations
             leaf       Leaf procedures optimizations
             profile    Use profiling information

For example, to enable all the optimization but dead code elimination and inlining, you can use:

        -O=all,-deadce,-inline

-V, --version

Prints JIT version information.

--debug

Turns on the debugging mode in the runtime. If an assembly was compiled with debugging information, it will produce line number information for stack traces.

--profile[=profiler[:profiler_args]]

Instructs the runtime to collect profiling information about execution times and memory allocation, and dump it at the end of the execution. If a profiler is not specified, the default profiler is used. profiler_args is a profiler-specific string of options for the profiler itself.

The default profiler accepts -time and -alloc to options to disable the time profiling or the memory allocation profilng.

--compile name

This compiles a method (namespace.name:methodname), this is used for testing the compiler performance or to examine the output of the code generator.

--compileall

Compiles all the methods in an assembly. This is used to test the compiler performance or to examine the output of the code generator

--graph=TYPE METHOD

This generates a postscript file with a graph with the details about the specified method (namespace.name:methodname). This requires `dot' and ghostview to be installed (it expects Ghostview to be called "gv").

The following graphs are available:

          cfg        Control Flow Graph (CFG)
          dtree      Dominator Tree
          code       CFG showing code
          ssa        CFG showing code after SSA translation
          optcode    CFG showing code after IR optimizations

Some graphs will only be available if certain optimizations are turned on.

--ncompile

Instruct the runtime on the number of times that the method specified by --compile (or all the methods if --compileall is used) to be compiled. This is used for testing the code generator performance.

-v, --verbose

Increases the verbosity level, each time it is listed, increases the verbosity level to include more information (including, for example, a disassembly of the native code produced, code selector info etc.).

--break method

Inserts a breakpoint before the method whose name is `method' (namespace.class:methodname). Use `Main' as method name to insert a breakpoint on the application's main method.

--breakonex

Inserts a breakpoint on exceptions. This allows you to debug your application with a native debugger when an exception is thrown.

--trace[=expression]

Shows method names as they are invoked. By default all methods are traced.

The trace can be customized to include or exclude methods, classes or assemblies. A trace expression is a comma separated list of targets, each target can be prefixed with a minus sign to turn off a particular target. The words `program' and `all' have special meaning. `program' refers to the main program being executed, and `all' means all the method calls.

Assemblies are specified by their name, for example, to trace all calls in the System assembly, use:

        mono --trace=System app.exe

        mono --trace=T:System.String app.exe

        mono --trace=M:System.Console:WriteLine app.exe

        mono --trace=T:System.String,T:System.Random app.exe

        mono --trace=T:System.String,-M:System.String:Concat

        mono --trace=N:System.Xml

GC_DONT_GC

Turns off the garbage collection in Mono. This should be only used for debugging purposes

MONO_ASPNET_NODELETE

If set to any value, temporary source files generated by ASP.NET support classes will not be removed. They will be kept in the user's temporary directory.

MONO_CFG_DIR

If set, this variable overrides the default system configuration directory ($PREFIX/etc). It's used to locate machine.config file.

MONO_CONFIG

If set, this variable overrides the default runtime configuration file ($PREFIX/etc/mono/config). The --config command line options overrides the environment variable.

MONO_LOG_LEVEL

If set, the logging level is changed to the set value. Possible values are "error", "critical", "warning", "message", "info", "debug". The default value is "error". Messages with a logging level greater then or equal to the log level will be printed to stdout/stderr.

MONO_LOG_MASK

If set, the log mask is changed to the set value. Possible values are "asm" (assembly loader), "type", "dll" (native library loader), "gc" (garbage collector), "cfg" (config file loader), "all". The default value is "all". Changing the mask value allows you to display only messages for a certain component. You can use multiple masks by comma separating them. For example to see config file messages and assembly loader messages set you mask to "asm,cfg".

MONO_DEBUG

If set, enables some features of the runtime useful for debugging. It makes the runtime display the stack traces for all the threads running and exit when mono is interrupted (Ctrl-C) and print some additional messages on error conditions. It may not exit cleanly. Use at your own risk.

MONO_DISABLE_AIO

If set, tells mono NOT to attempt using native asynchronous I/O services. In that case, the threadpool is used for asynchronous I/O on files and sockets.

MONO_DISABLE_SHM

If this variable is set, it disables the shared memory part of the Windows I/O Emulation layer, and handles (files, events, mutexes, pipes) will not be shared across processes. Process creation is also disabled. This option is only available on Unix.

MONO_EGD_SOCKET

For platforms that do not otherwise have a way of obtaining random bytes this can be set to the name of a file system socket on which an egd or prngd daemon is listening.

MONO_EXTERNAL_ENCODINGS

If set, contains a colon-separated list of text encodings to try when turning externally-generated text (e.g. command-line arguments or filenames) into Unicode. The encoding names come from the list provided by iconv, and the special case "default_locale" which refers to the current locale's default encoding.

When reading externally-generated text strings UTF-8 is tried first, and then this list is tried in order with the first successful conversion ending the search. When writing external text (e.g. new filenames or arguments to new processes) the first item in this list is used, or UTF-8 if the environment variable is not set.

MONO_MANAGED_WATCHER

If set to any value, System.IO.FileSystemWatcher will use the default managed implementation (slow). If unset, mono will try to use FAM under Unix systems and native API calls on Windows, falling back to the managed implementation on error.

MONO_PATH

Provides a search path to the runtime where to look for library files. Directories are separated by the platform path separator (colons on unix). Example: /home/username/lib:/usr/local/mono/lib

MONO_GAC_PREFIX

Provides a prefix the runtime uses to look for Global Assembly Caches. Directories are separated by the platform path separator (colons on unix). MONO_GAC_PREFIX should point to the top directory of a prefixed install. Or to the directory provided in the gacutil /gacdir command. Example: /home/username/.mono:/usr/local/mono/

MONO_SHARED_DIR

If set its the directory where the ".wapi" handle state is stored. This is the directory where the Windows I/O Emulation layer stores its shared state data (files, events, mutexes, pipes). By default Mono will store the ".wapi" directory in the users's home directory.

/etc/mono/config, ~/.mono/config

Mono runtime configuration file. See the mono-config(5) manual page for more information.

For ASP.NET-related documentation, see the xsp(1) manual page