| bytes | Package bytes implements functions for the manipulation of byte slices. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| go/format | Package format implements standard formatting of Go source. |
| io/ioutil | Package ioutil implements some I/O utility functions. |
| path/filepath | Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths. |
| 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. |
| text/template | Package template implements data-driven templates for generating textual output. |