| bufio | Package bufio implements buffered I/O. It wraps an io.Reader or io.Writer object, creating another object (Reader or Writer) that also implements the interface but provides buffering and some help for textual I/O. |
| bytes | Package bytes implements functions for the manipulation of byte slices. |
| flag | Package flag implements command-line flag parsing. |
| 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 | Package io provides basic interfaces to I/O primitives. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| text/template | Package template implements data-driven templates for generating textual output. |