| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| flag | Package flag implements command-line flag parsing. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| golang.org/x/tools/internal/bisect | Package bisect can be used by compilers and other programs to serve as a target for the bisect debugging tool. |
| io | Package io provides basic interfaces to I/O primitives. |
| log | Package log implements a simple logging package. |
| math/bits | Package bits implements bit counting and manipulation functions for the predeclared unsigned integer types. |
| math/rand | Package rand implements pseudo-random number generators suitable for tasks such as simulation, but it should not be used for security-sensitive work. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| os/exec | Package exec runs external commands. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| time | Package time provides functionality for measuring and displaying time. |