| archive/tar | Package tar implements access to tar archives. |
| bufio | Package bufio implements buffered I/O. |
| compress/gzip | Package gzip implements reading and writing of gzip format compressed files, as specified in RFC 1952. |
| crypto/hmac | Package hmac implements the Keyed-Hash Message Authentication Code (HMAC) as defined in U.S. |
| crypto/md5 | Package md5 implements the MD5 hash algorithm as defined in RFC 1321. |
| crypto/sha1 | Package sha1 implements the SHA1 hash algorithm as defined in RFC 3174. |
| crypto/tls | Package tls partially implements TLS 1.2, as specified in RFC 5246. |
| crypto/x509 | Package x509 parses X.509-encoded keys and certificates. |
| encoding/json | Package json implements encoding and decoding of JSON objects as defined in RFC 4627. |
| errors | Package errors implements functions to manipulate errors. |
| 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/build | Package build contains constants for the Go continous build system. |
| golang.org/x/build/buildlet | Package buildlet contains client tools for working with a buildlet server. |
| golang.org/x/build/envutil | Package envutil provides utilities for working with environment variables. |
| golang.org/x/build/pargzip | Package pargzip contains a parallel gzip writer implementation. |
| golang.org/x/build/revdial | Package revdial implements a Dialer and Listener which work together to turn an accepted connection (for instance, a Hijacked HTTP request) into a Dialer which can then create net.Conns connecting back to the original dialer, which then gets a net.Listener accepting those conns. |
| google.golang.org/cloud/compute/metadata | Package metadata provides access to Google Compute Engine (GCE) metadata and API service accounts. |
| io | Package io provides basic interfaces to I/O primitives. |
| io/ioutil | Package ioutil implements some I/O utility functions. |
| log | Package log implements a simple logging package. |
| net | Package net provides a portable interface for network I/O, including TCP/IP, UDP, domain name resolution, and Unix domain sockets. |
| net/http | Package http provides HTTP client and server implementations. |
| net/url | Package url parses URLs and implements query escaping. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| os/exec | Package exec runs external commands. |
| path | Package path implements utility routines for manipulating slash-separated paths. |
| 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. |
| 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. |