How to Use the Command "monodis" (with examples)

The “monodis” command is a Mono Common Intermediate Language (CIL) disassembler. It allows you to disassemble Mono assemblies into textual CIL code, view assembly information, list assembly references, list assembly methods, and extract embedded resources. This article will illustrate each of these use cases with examples.

Use case 1: Disassemble an assembly to textual CIL

Code:

monodis path/to/assembly.exe

Motivation: Disassembling an assembly to textual CIL allows developers to analyze the intermediate language code generated by the compiler. This can be useful for debugging or understanding the inner workings of a compiled Mono assembly.

Explanation:

• monodis: The command name to access the Mono disassembler.
• path/to/assembly.exe: The path to the assembly file that you want to disassemble.

Example output:

.assembly extern mscorlib
{
    .publickeytoken = (B7 7A 5C 56 19 34 E0 89)
    .ver 4:0:0:0
}

Use case 2: Save the output to a file

Code:

monodis --output=path/to/output.il path/to/assembly.exe

Motivation: Saving the output to a file allows developers to analyze the disassembled code at a later time or share it with others.

Explanation:

• monodis: The command name to access the Mono disassembler.
• --output=path/to/output.il: The flag to specify the file path where the disassembled code will be saved.
• path/to/assembly.exe: The path to the assembly file that you want to disassemble.

Example output: The disassembled code will be saved to the specified output file path.

Use case 3: Show information about an assembly

Code:

monodis --assembly path/to/assembly.dll

Motivation: Viewing information about an assembly provides visibility into its metadata, version details, and public key token.

Explanation:

• monodis: The command name to access the Mono disassembler.
• --assembly: The flag to specify that the information about the assembly should be displayed.
• path/to/assembly.dll: The path to the assembly file for which you want to view information.

Example output:

.assembly extern mscorlib
{
    .publickeytoken = (B7 7A 5C 56 19 34 E0 89)
    .ver 4:0:0:0
}

Use case 4: List the references of an assembly

Code:

monodis --assemblyref path/to/assembly.exe

Motivation: Listing the references of an assembly helps in identifying the dependencies of the assembly and understanding its dependencies on other NuGet packages or libraries.

Explanation:

• monodis: The command name to access the Mono disassembler.
• --assemblyref: The flag to specify that the assembly references should be listed.
• path/to/assembly.exe: The path to the assembly file for which you want to list the references.

Example output:

mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

Use case 5: List all the methods in an assembly

Code:

monodis --method path/to/assembly.exe

Motivation: Listing all the methods in an assembly allows developers to analyze the available methods in the assembly and understand its functionality.

Explanation:

• monodis: The command name to access the Mono disassembler.
• --method: The flag to specify that all the methods in the assembly should be listed.
• path/to/assembly.exe: The path to the assembly file for which you want to list the methods.

Example output:

System.Void Program::Main(System.String[])
System.Void Program::Method1()
System.String Program::Method2()

Use case 6: Show a list of resources embedded within an assembly

Code:

monodis --manifest path/to/assembly.dll

Motivation: Viewing a list of embedded resources provides an understanding of the additional files or data stored within the assembly, such as images, configuration files, or language resources.

Explanation:

• monodis: The command name to access the Mono disassembler.
• --manifest: The flag to specify that the list of embedded resources should be displayed.
• path/to/assembly.dll: The path to the assembly file for which you want to view the embedded resources.

Example output:

_resources/en-US/Resource1.resources
_resources/en-US/Resource2.resources

Use case 7: Extract all the embedded resources to the current directory

Code:

monodis --mresources path/to/assembly.dll

Motivation: Extracting all the embedded resources from an assembly allows developers to access and manipulate these resources separately, such as copying them to another location or modifying them directly.

Explanation:

• monodis: The command name to access the Mono disassembler.
• --mresources: The flag to specify that all the embedded resources should be extracted.
• path/to/assembly.dll: The path to the assembly file from which you want to extract the embedded resources.

Example output: The embedded resources will be extracted to the current directory.

Conclusion:

The “monodis” command is a powerful tool for disassembling Mono assemblies, viewing assembly information, listing references and methods, and working with embedded resources. By utilizing the various use cases outlined in this article, developers can gain a deeper understanding of the compiled code and its dependencies, and manipulate the embedded resources as needed.