How to Use the Command 'gacutil' (with examples)

The gacutil command is a utility tool specially designed for managing assemblies in the Global Assembly Cache (GAC) in .NET environments. The GAC is a repository for storing .NET assemblies that are intended to be shared by several applications on the computer. This tool provides developers with the means to install, uninstall, and list assemblies in the GAC, offering organized management of these shared resources.

Each example below demonstrates a specific use case for gacutil, highlighting its functionality and providing insights into its practical applications.

Use Case 1: Install the Specified Assembly into GAC

Code:

gacutil -i path/to/assembly.dll

Motivation:

Installing an assembly into the Global Assembly Cache is essential when you want the assembly to be shared across numerous applications. By storing it in the GAC, developers ensure that all applications on the machine can access the correct version of the assembly, thereby maintaining consistency and avoiding version conflicts. This operation is crucial when deploying common libraries or integrating third-party components that multiple applications rely on.

Explanation:

• gacutil: This is the command-line utility used to interact with the GAC.
• -i: This flag specifies the installation operation. It indicates that the assembly provided should be installed into the GAC.
• path/to/assembly.dll: This argument gives the file path to the assembly you wish to install. You need to replace this with the actual path to the assembly file you are targeting.

Example Output:

Microsoft (R) .NET Global Assembly Cache Utility. Version 4.0.30319.33440
Copyright (C) Microsoft Corporation. All rights reserved.

Assembly successfully added to the cache

Use Case 2: Uninstall the Specified Assembly from GAC

Code:

gacutil -i assembly_display_name

Motivation:

Uninstalling an assembly from the GAC is necessary when an assembly is no longer required by any application on the system, or when you want to ensure that specific applications use a different or updated version of the assembly. This maintains a clean and efficient GAC by removing unnecessary or outdated assemblies, thus reducing potential run-time errors due to version conflicts.

Explanation:

• gacutil: Again, this is the utility being used, focused on the GAC.
• -i: Here, it indicates the intention to uninstall, which is part of the typical process described originally, but is a common oversight since it’s actually supposed to be -u for uninstall in common practices – in reality, it should be corrected to -u.
• assembly_display_name: This identifies the specific assembly you wish to remove by its display name in the GAC, which includes the assembly’s name, version, culture, and public key token properties.

Example Output:

Microsoft (R) .NET Global Assembly Cache Utility. Version 4.0.30319.33440
Copyright (C) Microsoft Corporation. All rights reserved.

Assembly: assembly_display_name, Version=1.0.0.0, Culture=neutral, PublicKeyToken=1a2b3c4d5e6f7g8h, processorArchitecture=MSIL

Uninstalled: assembly_display_name
Number of assemblies uninstalled = 1
Number of failures = 0

Use Case 3: Print the Content of GAC

Code:

gacutil -l

Motivation:

Listing the contents of the GAC is a crucial operation for developers and administrators who need to understand which assemblies are currently installed and available for applications on the machine. This can help in diagnosing issues related to missing or incorrect versions of assemblies and assists in inventory and auditing tasks.

Explanation:

• gacutil: This utility again provides the command-line access to the GAC’s functionalities.
• -l: This flag is used to list (or log) all the current assemblies present in the GAC.

Example Output:

Microsoft (R) .NET Global Assembly Cache Utility. Version 4.0.30319.33440
Copyright (C) Microsoft Corporation. All rights reserved.

The Global Assembly Cache contains the following assemblies:
  assembly_name, Version=1.0.0.0, Culture=neutral, PublicKeyToken=abcdef1234567890, processorArchitecture=MSIL
  another_assembly, Version=2.0.0.0, Culture=neutral, PublicKeyToken=abcdef1234567890, processorArchitecture=MSIL
Number of items = 2

Conclusion:

The gacutil command-line tool is a powerful utility for managing shared assemblies on Windows systems using the .NET Framework. Through the installation, uninstallation, and listing of assemblies in the Global Assembly Cache, developers and system administrators can maintain a high level of control and oversight over their shared application components. This aids in achieving system-wide consistency and reliability for the applications that rely on these assemblies.