## Tools {#tools}

### Go command {#go-command}

Setting the `GOROOT_FINAL` environment variable no longer has an effect
([#62047](https://go.dev/issue/62047)).
Distributions that install the `go` command to a location other than
`$GOROOT/bin/go` should install a symlink instead of relocating
or copying the `go` binary.

# This file contains the initial defaults for go command configuration.
# Values set by 'go env -w' and written to the user's go/env file override these.
# The environment overrides everything else.

# Use the Go module mirror and checksum database by default.
# See https://proxy.golang.org for details.
GOPROXY=https://proxy.golang.org,direct
GOSUMDB=sum.golang.org

# Automatically download newer toolchains as directed by go.mod files.

## Tools {#tools}

### Go command {#go-command}

# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.

# Run go tool dist to install a command.
# The -v causes dist to print the name of each directory as it runs.
# The -vv causes dist to print each build command as it runs.
# go tool dist clean cleans all directories, not just this one,
# but it's as close as we can get.

# Default target (first).
install:

set to the clang wrapper that invokes clang for iOS. For example, this command runs
 all.bash on the iOS emulator:

	GOOS=ios GOARCH=amd64 CGO_ENABLED=1 CC_FOR_TARGET=$(pwd)/../misc/ios/clangwrap.sh ./all.bash

If CC_FOR_TARGET is not set when the toolchain is built (make.bash or all.bash), CC
can be set on the command line. For example,

are also treated as invalid.
(Older toolchains ignore `//go:debug` directives entirely.)

The defaults that will be compiled into a main package
are reported by the command:

{{raw `
	go list -f '{{.DefaultGODEBUG}}' my/main/package
`}}

Only differences from the base Go toolchain defaults are reported.

When testing a package, `//go:debug` lines in the `*_test.go`

Vendoring in std and cmd
========================

The Go command maintains copies of external packages needed by the
standard library in the src/vendor and src/cmd/vendor directories.

There are two modules, std and cmd, defined in src/go.mod and
src/cmd/go.mod. When a package outside std or cmd is imported
by a package inside std or cmd, the import path is interpreted
as if it had a "vendor/" prefix. For example, within "crypto/tls",

pkg os, var ErrNotExist error
pkg os, var ErrPermission error
pkg os, var Interrupt Signal
pkg os, var Kill Signal
pkg os, var Stderr *File
pkg os, var Stdin *File
pkg os, var Stdout *File
pkg os/exec, func Command(string, ...string) *Cmd
pkg os/exec, func LookPath(string) (string, error)
pkg os/exec, method (*Cmd) CombinedOutput() ([]uint8, error)
pkg os/exec, method (*Cmd) Output() ([]uint8, error)