| 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. |
| github.com/coreos/etcd/pkg/types | Package types declares various data types and implements type-checking functions. |
| github.com/coreos/pkg/capnslog | |
| github.com/spf13/pflag | Package pflag is a drop-in replacement for Go's flag package, implementing POSIX/GNU-style --flags. |
| net/url | Package url parses URLs and implements query escaping. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |