Golang input/output: Difference between revisions
From wikinotes
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= Files = | = Files = |
Revision as of 16:17, 18 June 2022
Documentation
fmt
https://pkg.go.dev/fmt@go1.18.2 io/ioutil
(read/write)https://pkg.go.dev/io/ioutil@go1.18.3 io/fs
(filesystem)https://pkg.go.dev/io/fs@go1.18.3 textproto
(sockets)https://pkg.go.dev/net/textproto@go1.18.3
Basics
require "fmt" fmt.Println("foo") // print to stdout with newline fmt.Printf("%v", 123) // print formatted string to stdout (no newline) fmt.Fprintf(os.Stdout, "%v", 123) // prints formatted string to writable object (ex. STDOUT, STERR, ..) fmt.Sprintf("%v", 123) // returns formatted string (no newline)Format Syntax
Printf/Sprintf/Fprintf all take format specifiers.
See full docs here, but here's some really useful formats:# general %v # value %T # type # number-bases %b # binary %x # hex %o # octal %d # decimal # number types %i # int %f # float # strings %s # string %q # quoted/escaped go string %c # unicode-char for num
stdin, stdout, stderr
fmt.Fprintln(os.Stdout, "writes stdout") fmt.Fprintln(os.Stderr, "writes stderr")
Files
require "os" os.WriteFile("/var/tmp/foo.txt", []byte("abc"), 0644) conts, err := os.ReadFile("/var/tmp/foo.txt")
Networking
Sockets
net.Dial()
creates sockets of various types.import "net" // unix socketfile conn, err = net.Dial("unix", "/var/tmp/foo.sock") // inet socket conn, err = net.Dial("tcp", "10.10.10.10:6600") defer conn.Close() // sending message to socket _, err = conn.Write([]byte("search title 'it ceases to be'")) reply := make([]byte, 1024) _, err = conn.Read(reply) fmt.Println(string(reply))HTTP