Purpose: This variable allows you to specify additional flags for the go command.

Usage: Set GOFLAGS to include additional command-line flags when running go commands.

1. Enabling Verbose Output:

   GOFLAGS=-v 
   go build main.go

   This command compiles the main.go program with the -v flag, which stands for “verbose.” It provides detailed information about the build process, including which files are being compiled and linked.

2. Setting Output Directory:

   GOFLAGS=-o myapp 
   go build main.go

   Here, the -o flag is used to specify the output file’s name as myapp. This can be handy when you want to customize the name of the generated binary.

3. Building with Specific Tags:

   GOFLAGS=-tags=mytag 
   go build main.go

   You can use the -tags flag to build your Go program with specific build tags. Build tags are a way to include or exclude certain parts of your code during compilation based on conditions defined in your source code.

4. Cross-Compiling with GOOS and GOARCH:

   GOFLAGS="-v -ldflags '-s -w' -trimpath" 
   GOOS=linux 
   GOARCH=amd64 
   go build main.go

   In this example, GOFLAGS is used to pass a combination of flags to customize the build process. It includes the -v flag for verbose output, -ldflags to specify linker flags, and -trimpath to trim the source path. Additionally, GOOS and GOARCH are set to cross-compile the program for Linux on an AMD64 architecture.

5. Modifying Build Mode:

   GOFLAGS="-buildmode=shared" 
   go build main.go

   Here, GOFLAGS is used to specify the build mode as “shared.” This can be useful when you want to create a shared library or plugin using Go.

6. Running Tests with Parallelism:

   GOFLAGS="-p 2" 
   go test ./…

   You can control the parallelism of your Go test runs using the -p flag. In this example, GOFLAGS is set to run tests with a maximum of 2 parallel processes.

7. Running Benchmarks with Custom Timing:

   GOFLAGS="-benchtime=2s" 
   go test -bench=. ./…

   The -benchtime flag allows you to specify the duration for which benchmark tests should run. Here, GOFLAGS is used to set the benchmark time to 2 seconds.

8. Using Custom Environment Variables:

   GOFLAGS="GOARCH=arm64 GOOS=linux" 
   go build main.go

   You can use GOFLAGS to set custom environment variables for the Go build process. In this case, it specifies the GOARCH and GOOS variables to cross-compile for ARM64 architecture on Linux.