gofmt

gofmt is a tool in the Go programming language toolchain that formats Go source code. It applies a canonical formatting style for Go code, ensuring consistent indentation, line breaks, and spacing across files and projects. The formatting is defined by the Go team and is used by the standard library and most Go codebases.

It can format individual files or entire packages. The common wrapper go fmt formats all packages in the current module or directory; gofmt can read from standard input and write to standard output; with the -w flag it writes changes back to source files. The -d flag shows a diff of suggested changes, and -l lists files that would be modified. The -s flag enables additional simplifications. The -r option allows applying a rewrite rule to rewrite code patterns while formatting.

History and design: It enforces uniform style to improve readability and consistency; it is part of the Go toolchain and has no separate user-configurable style. The rules are fixed and opinionated, which minimizes debates about formatting. gofmt is widely adopted and can be integrated into editors, pre-commit hooks, and continuous integration pipelines to automate formatting as part of development workflows.