| bytes | Package bytes implements functions for the manipulation of byte slices. |
| cmd/go/internal/base | Package base defines shared basic pieces of the go command, in particular logging and the Command structure. |
| cmd/go/internal/cfg | Package cfg holds configuration shared by multiple parts of the go command. |
| cmd/go/internal/envcmd | Package envcmd implements the “go env” command. |
| cmd/go/internal/web | Package web defines minimal helper routines for accessing HTTP/HTTPS resources without requiring external dependencies on the net package. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| io | Package io provides basic interfaces to I/O primitives. |
| io/ioutil | Package ioutil implements some I/O utility functions. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| os/exec | Package exec runs external commands. |
| path/filepath | Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths. |
| regexp | Package regexp implements regular expression search. |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |