【Go】基本的なgoコマンド

1go run [build flags] [-exec xprog] package [arguments...]

1package main
2
3import "fmt"
4
5func main() {
6	fmt.Println("Hello World!!")
7}

1❯ go run main.go
2Hello World!!
3
4❯ ls
5main.go

1go build [-o output] [build flags] [packages]

1package main
2
3import "fmt"
4
5func main() {
6	fmt.Println("Hello World!!")
7}

1❯ go build main.go
2
3❯ ls
4main  main.go

1❯ go build -o hello-world main.go
2
3❯ ls
4hello-world  main.go

1go mod <command> [arguments]

1go mod init [module-path]

1go mod tidy [-e] [-v] [-x] [-go=version] [-compat=version]

1package main
2
3import "fmt"
4
5func main() {
6	fmt.Println("Hello World!!")
7}

1go mod init hello-world

1module hello-world
2
3go 1.20

1❯ go mod tidy
2
3❯ go build
4
5❯ ls
6go.mod  hello-world  main.go

1go install [build flags] [packages]

1❯ go install github.com/rakyll/hey@latest
2
3❯ hey -h
4flag needs an argument: -h
5Usage: hey [options...] <url>
6
7Options:
8  -n  Number of requests to run. Default is 200.
9  -c  Number of workers to run concurrently. Total number of requests cannot
10      be smaller than the concurrency level. Default is 50.
11  ...

1go fmt [-n] [-x] [packages]

1go install golang.org/x/tools/cmd/goimports@latest

1package main
2
3import "fmt"
4import "context" // 不要なライブラリ
5
6func main() {
7  fmt.Println("Hello World!!") // スペースによる字下げ
8}

1❯ goimports -l -w .
2main.go

1package main
2
3import "fmt"
4
5func main() {
6	fmt.Println("Hello World!!")
7}

1go vet [-C dir] [-n] [-x] [-vettool prog] [build flags] [vet flags] [packages]

1❯ go tool vet help
2vet is a tool for static analysis of Go programs.
3
4vet examines Go source code and reports suspicious constructs,
5such as Printf calls whose arguments do not align with the format
6string. It uses heuristics that do not guarantee all reports are
7genuine problems, but it can find errors not caught by the compilers.
8
9Registered analyzers:
10
11    asmdecl      report mismatches between assembly files and Go declarations
12    assign       check for useless assignments
13    atomic       check for common mistakes using the sync/atomic package
14    bools        check for common mistakes involving boolean operators
15    buildtag     check that +build tags are well-formed and correctly located
16    cgocall      detect some violations of the cgo pointer passing rules
17    composites   check for unkeyed composite literals
18    copylocks    check for locks erroneously passed by value
19    errorsas     report passing non-pointer or non-error values to errors.As
20    framepointer report assembly that clobbers the frame pointer before saving it
21    httpresponse check for mistakes using HTTP responses
22    ifaceassert  detect impossible interface-to-interface type assertions
23    loopclosure  check references to loop variables from within nested functions
24    lostcancel   check cancel func returned by context.WithCancel is called
25    nilfunc      check for useless comparisons between functions and nil
26    printf       check consistency of Printf format strings and arguments
27    shift        check for shifts that equal or exceed the width of the integer
28    sigchanyzer  check for unbuffered channel of os.Signal
29    stdmethods   check signature of methods of well-known interfaces
30    stringintconv check for string(int) conversions
31    structtag    check that struct field tags conform to reflect.StructTag.Get
32    testinggoroutine report calls to (*testing.T).Fatal from goroutines started by a test.
33    tests        check for common mistaken usages of tests and examples
34    timeformat   check for calls of (time.Time).Format or time.Parse with 2006-02-01
35    unmarshal    report passing non-pointer or non-interface values to unmarshal
36    unreachable  check for unreachable code
37    unsafeptr    check for invalid conversions of uintptr to unsafe.Pointer
38    unusedresult check for unused results of calls to some functions

1go install honnef.co/go/tools/cmd/staticcheck@latest

1package main
2
3import "fmt"
4
5func main() {
6	var x int = 10 // 未使用の変数
7	fmt.Println("Hello World!!")
8}

1❯ go vet
2# hello-world
3vet: ./main.go:6:6: x declared and not used