| archive/zip | Package zip provides support for reading and writing ZIP archives. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| golang.org/x/tools/internal/testenv | Package testenv contains helper functions for skipping tests based on which tools are present in the environment. |
| 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. |
| path/filepath | Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |