Package bufio implements buffered I/O.

Package builtin provides documentation for Go's predeclared identifiers.

Package bytes implements functions for the manipulation of byte slices.

Package crypto collects common cryptographic constants.

Package errors implements functions to manipulate errors.

Package expvar provides a standardized interface to public variables, such as operation counters in servers.

Package flag implements command-line flag parsing.

Package fmt implements formatted I/O with functions analogous to C's printf and scanf.

Package hash provides interfaces for hash functions.

Package html provides functions for escaping and unescaping HTML text.

Package image implements a basic 2-D image library.

Package io provides basic interfaces to I/O primitives.

Package log implements a simple logging package.

Package math provides basic constants and mathematical functions.

Package mime implements parts of the MIME spec.

Package net provides a portable interface for network I/O, including TCP/IP, UDP, domain name resolution, and Unix domain sockets.

Package os provides a platform-independent interface to operating system functionality.

Package path implements utility routines for manipulating slash-separated paths.

Package reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types.

Package regexp implements regular expression search.

Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines.

Package sort provides primitives for sorting slices and user-defined collections.

Package strconv implements conversions to and from string representations of basic data types.

Package strings implements simple functions to manipulate strings.

Package sync provides basic synchronization primitives such as mutual exclusion locks.

Package syscall contains an interface to the low-level operating system primitives.

Package testing provides support for automated testing of Go packages.

Package time provides functionality for measuring and displaying time.

Package unicode provides data and functions to test some properties of Unicode code points.

Package unsafe contains operations that step around the type safety of Go programs.