2.终端命令

help

help
获取帮助

go help

bug

start a bug report
打开默认浏览器并开始一个新的Bug上报

go help bug

usage: go bug
Bug opens the default browser and starts a new bug report.
The report includes useful system information.

build

compile packages and dependencies
编译包和依赖

go help build

usage: go build [-o output] [build flags] [packages]

Build compiles the packages named by the import paths,
along with their dependencies, but it does not install the results.

If the arguments to build are a list of .go files from a single directory,
build treats them as a list of source files specifying a single package.

When compiling packages, build ignores files that end in '_test.go'.

When compiling a single main package, build writes
the resulting executable to an output file named after
the first source file ('go build ed.go rx.go' writes 'ed' or 'ed.exe')
or the source code directory ('go build unix/sam' writes 'sam' or 'sam.exe').
The '.exe' suffix is added when writing a Windows executable.

When compiling multiple packages or a single non-main package,
build compiles the packages but discards the resulting object,
serving only as a check that the packages can be built.

The -o flag forces build to write the resulting executable or object
to the named output file or directory, instead of the default behavior described
in the last two paragraphs. If the named output is an existing directory or
ends with a slash or backslash, then any resulting executables
will be written to that directory.

The -i flag installs the packages that are dependencies of the target.
The -i flag is deprecated. Compiled packages are cached automatically.

The build flags are shared by the build, clean, get, install, list, run,
and test commands:

-a
force rebuilding of packages that are already up-to-date.
-n
print the commands but do not run them.
-p n
the number of programs, such as build commands or
test binaries, that can be run in parallel.
The default is GOMAXPROCS, normally the number of CPUs available.
-race
enable data race detection.
Supported only on linux/amd64, freebsd/amd64, darwin/amd64, windows/amd64,
linux/ppc64le and linux/arm64 (only for 48-bit VMA).
-msan
enable interoperation with memory sanitizer.
Supported only on linux/amd64, linux/arm64
and only with Clang/LLVM as the host C compiler.
On linux/arm64, pie build mode will be used.
-v
print the names of packages as they are compiled.
-work
print the name of the temporary work directory and
do not delete it when exiting.
-x
print the commands.

-asmflags '[pattern=]arg list'
arguments to pass on each go tool asm invocation.
-buildmode mode
build mode to use. See 'go help buildmode' for more.
-compiler name
name of compiler to use, as in runtime.Compiler (gccgo or gc).
-gccgoflags '[pattern=]arg list'
arguments to pass on each gccgo compiler/linker invocation.
-gcflags '[pattern=]arg list'
arguments to pass on each go tool compile invocation.
-installsuffix suffix
a suffix to use in the name of the package installation directory,
in order to keep output separate from default builds.
If using the -race flag, the install suffix is automatically set to race
or, if set explicitly, has _race appended to it. Likewise for the -msan
flag. Using a -buildmode option that requires non-default compile flags
has a similar effect.
-ldflags '[pattern=]arg list'
arguments to pass on each go tool link invocation.
-linkshared
build code that will be linked against shared libraries previously
created with -buildmode=shared.
-mod mode
module download mode to use: readonly, vendor, or mod.
By default, if a vendor directory is present and the go version in go.mod
is 1.14 or higher, the go command acts as if -mod=vendor were set.
Otherwise, the go command acts as if -mod=readonly were set.
See https://golang.org/ref/mod#build-commands for details.
-modcacherw
leave newly-created directories in the module cache read-write
instead of making them read-only.
-modfile file
in module aware mode, read (and possibly write) an alternate go.mod
file instead of the one in the module root directory. A file named
"go.mod" must still be present in order to determine the module root
directory, but it is not accessed. When -modfile is specified, an
alternate go.sum file is also used: its path is derived from the
-modfile flag by trimming the ".mod" extension and appending ".sum".
-overlay file
read a JSON config file that provides an overlay for build operations.
The file is a JSON struct with a single field, named 'Replace', that
maps each disk file path (a string) to its backing file path, so that
a build will run as if the disk file path exists with the contents
given by the backing file paths, or as if the disk file path does not
exist if its backing file path is empty. Support for the -overlay flag
has some limitations: importantly, cgo files included from outside the
include path must be in the same directory as the Go package they are
included from, and overlays will not appear when binaries and tests are
run through go run and go test respectively.
-pkgdir dir
install and load all packages from dir instead of the usual locations.
For example, when building with a non-standard configuration,
use -pkgdir to keep generated packages in a separate location.
-tags tag,list
a comma-separated list of build tags to consider satisfied during the
build. For more information about build tags, see the description of
build constraints in the documentation for the go/build package.
(Earlier versions of Go used a space-separated list, and that form
 is deprecated but still recognized.)
-trimpath
remove all file system paths from the resulting executable.
Instead of absolute file system paths, the recorded file names
will begin with either "go" (for the standard library),
or a module path@version (when using modules),
or a plain import path (when using GOPATH).
-toolexec 'cmd args'
a program to use to invoke toolchain programs like vet and asm.
For example, instead of running asm, the go command will run
'cmd args /path/to/asm <arguments for asm>'.
The TOOLEXEC_IMPORTPATH environment variable will be set,
matching 'go list -f {{.ImportPath}}' for the package being built.

The -asmflags, -gccgoflags, -gcflags, and -ldflags flags accept a
space-separated list of arguments to pass to an underlying tool
during the build. To embed spaces in an element in the list, surround
it with either single or double quotes. The argument list may be
preceded by a package pattern and an equal sign, which restricts
the use of that argument list to the building of packages matching
that pattern (see 'go help packages' for a description of package
              patterns). Without a pattern, the argument list applies only to the
packages named on the command line. The flags may be repeated
with different patterns in order to specify different arguments for
different sets of packages. If a package matches patterns given in
multiple flags, the latest match on the command line wins.
For example, 'go build -gcflags=-S fmt' prints the disassembly
only for package fmt, while 'go build -gcflags=all=-S fmt'
prints the disassembly for fmt and all its dependencies.

For more about specifying packages, see 'go help packages'.
For more about where packages and binaries are installed,
run 'go help gopath'.
For more about calling between Go and C/C++, run 'go help c'.

Note: Build adheres to certain conventions such as those described
by 'go help gopath'. Not all projects can follow these conventions,
however. Installations that have their own conventions or that use
a separate software build system may choose to use lower-level
invocations such as 'go tool compile' and 'go tool link' to avoid
some of the overheads and design decisions of the build tool.

See also: go install, go get, go clean.

参数	说明
[-o output]	指定输出
[build flags]	编译参数
[packages]	包列表

[build flags]编译参数	说明
-C dir	切换至指定目录
-a	强制重新构建
-n	指令打印但不运行指令
-p n	可以并行运行的程序数量（P的数量）。默认值是GOMAXPROCS，通常是可用cpu的数量。
-race	启用数据竞争检测。
-msan	启用与内存清理程序的交互
-asan	启用与地址清理器的交互
-cover	启用代码覆盖检测(需要设置GOEXPERIMENT=coverageredesign)
-coverpkg pattern1,pattern2,pattern3	对于以包main为目标的构建，对每个匹配模式的包应用覆盖率分析。默认情况下是对Go main模块中的包应用覆盖率分析
-v	在编译包时打印包名
-work	打印临时工作目录的名称，退出时不删除
-x	运行时打印指令
-asmflags ‘[pattern=]arg list’	参数传递给每个go工具asm调用
-buildmode mode	要使用的构建模式，参见go help buildmode
-buildvcs	是否用版本控制信息(true， false，或auto)标记二进制文件。默认情况下(auto)，如果主包、包含它的主模块和当前目录都在同一个存储库中，则版本控制信息被戳印到二进制文件中。使用-buildvcs=false总是忽略版本控制信息，如果版本控制信息可用，但由于缺少工具或目录结构不明确而无法包含，则使用-buildvcs=true输出错误。
-compiler name	要使用的编译器的名称(gccgo或gc)。
-gccgoflags ‘[pattern=]arg list’	参数传递给每个gccgo compiler/linker 调用。
-gcflags ‘[pattern=]arg list’	参数传递给每个go tool compile调用。
-installsuffix suffix	在包安装目录名称中使用的后缀，以便将输出与默认构建分开。 如果使用-race标志，安装后缀将自动设置为race，如果显式设置，则将_race附加到后面。-msan和-asan标志也是如此。使用需要非默认编译标志的-buildmode选项也有类似的效果。
-ldflags ‘[pattern=]arg list’	参数传递给每个go tool link调用。
-linkshared	构建代码将链接到之前使用-buildmode=shared创建的共享库。
-mod mode	mod下载模式使用: readonly，vendor，或mod
-modcacherw	在模块缓存中保持新创建的目录为读写状态，而不是使其为只读状态。
-modfile file	在模块感知模式下，读取(也可能写入)一个备用go.mod文件，而不是模块根目录中的文件。
-overlay file	读取JSON配置文件，为构建操作提供覆盖。
-pgo file	指定配置文件的文件路径，用于配置文件引导优化(PGO)
-pkgdir dir	安装和加载所有包从dir而不是通常的位置。
-tags tag,list	以逗号分隔的附加构建标记列表。
-trimpath	从结果可执行文件中删除所有文件系统路径。
-toolexec ‘cmd args’	用于调用工具链程序(如vet和asm)的程序。

clean

remove object files and cached files
删除目标文件和缓存文件

go help clean

usage: go clean [clean flags] [build flags] [packages]

Clean removes object files from package source directories.
The go command builds most objects in a temporary directory,
so go clean is mainly concerned with object files left by other
tools or by manual invocations of go build.

If a package argument is given or the -i or -r flag is set,
clean removes the following files from each of the
source directories corresponding to the import paths:

	_obj/            old object directory, left from Makefiles
	_test/           old test directory, left from Makefiles
	_testmain.go     old gotest file, left from Makefiles
	test.out         old test log, left from Makefiles
	build.out        old test log, left from Makefiles
	*.[568ao]        object files, left from Makefiles

	DIR(.exe)        from go build
	DIR.test(.exe)   from go test -c
	MAINFILE(.exe)   from go build MAINFILE.go
	*.so             from SWIG

In the list, DIR represents the final path element of the
directory, and MAINFILE is the base name of any Go source
file in the directory that is not included when building
the package.

The -i flag causes clean to remove the corresponding installed
archive or binary (what 'go install' would create).

The -n flag causes clean to print the remove commands it would execute,
but not run them.

The -r flag causes clean to be applied recursively to all the
dependencies of the packages named by the import paths.

The -x flag causes clean to print remove commands as it executes them.

The -cache flag causes clean to remove the entire go build cache.

The -testcache flag causes clean to expire all test results in the
go build cache.

The -modcache flag causes clean to remove the entire module
download cache, including unpacked source code of versioned
dependencies.

For more about build flags, see 'go help build'.

For more about specifying packages, see 'go help packages'.

doc

show documentation for package or symbol
显示包或符号的文档

go help doc

usage: go doc [doc flags] [package|[package.]symbol[.methodOrField]]

Doc prints the documentation comments associated with the item identified by its
arguments (a package, const, func, type, var, method, or struct field)
followed by a one-line summary of each of the first-level items "under"
that item (package-level declarations for a package, methods for a type,
etc.).

Doc accepts zero, one, or two arguments.

Given no arguments, that is, when run as

	go doc

it prints the package documentation for the package in the current directory.
If the package is a command (package main), the exported symbols of the package
are elided from the presentation unless the -cmd flag is provided.

When run with one argument, the argument is treated as a Go-syntax-like
representation of the item to be documented. What the argument selects depends
on what is installed in GOROOT and GOPATH, as well as the form of the argument,
which is schematically one of these:

	go doc <pkg>
	go doc <sym>[.<methodOrField>]
	go doc [<pkg>.]<sym>[.<methodOrField>]
	go doc [<pkg>.][<sym>.]<methodOrField>

The first item in this list matched by the argument is the one whose documentation
is printed. (See the examples below.) However, if the argument starts with a capital
letter it is assumed to identify a symbol or method in the current directory.

For packages, the order of scanning is determined lexically in breadth-first order.
That is, the package presented is the one that matches the search and is nearest
the root and lexically first at its level of the hierarchy. The GOROOT tree is
always scanned in its entirety before GOPATH.

If there is no package specified or matched, the package in the current
directory is selected, so "go doc Foo" shows the documentation for symbol Foo in
the current package.

The package path must be either a qualified path or a proper suffix of a
path. The go tool's usual package mechanism does not apply: package path
elements like . and ... are not implemented by go doc.

When run with two arguments, the first must be a full package path (not just a
suffix), and the second is a symbol, or symbol with method or struct field.
This is similar to the syntax accepted by godoc:

	go doc <pkg> <sym>[.<methodOrField>]

In all forms, when matching symbols, lower-case letters in the argument match
either case but upper-case letters match exactly. This means that there may be
multiple matches of a lower-case argument in a package if different symbols have
different cases. If this occurs, documentation for all matches is printed.

Examples:
	go doc
		Show documentation for current package.
	go doc Foo
		Show documentation for Foo in the current package.
		(Foo starts with a capital letter so it cannot match
		a package path.)
	go doc encoding/json
		Show documentation for the encoding/json package.
	go doc json
		Shorthand for encoding/json.
	go doc json.Number (or go doc json.number)
		Show documentation and method summary for json.Number.
	go doc json.Number.Int64 (or go doc json.number.int64)
		Show documentation for json.Number's Int64 method.
	go doc cmd/doc
		Show package docs for the doc command.
	go doc -cmd cmd/doc
		Show package docs and exported symbols within the doc command.
	go doc template.new
		Show documentation for html/template's New function.
		(html/template is lexically before text/template)
	go doc text/template.new # One argument
		Show documentation for text/template's New function.
	go doc text/template new # Two arguments
		Show documentation for text/template's New function.

	At least in the current tree, these invocations all print the
	documentation for json.Decoder's Decode method:

	go doc json.Decoder.Decode
	go doc json.decoder.decode
	go doc json.decode
	cd go/src/encoding/json; go doc decode

Flags:
	-all
		Show all the documentation for the package.
	-c
		Respect case when matching symbols.
	-cmd
		Treat a command (package main) like a regular package.
		Otherwise package main's exported symbols are hidden
		when showing the package's top-level documentation.
	-short
		One-line representation for each symbol.
	-src
		Show the full source code for the symbol. This will
		display the full Go source of its declaration and
		definition, such as a function definition (including
		the body), type declaration or enclosing const
		block. The output may therefore include unexported
		details.
	-u
		Show documentation for unexported as well as exported
		symbols, methods, and fields.

env

print Go environment information
打印Go环境信息

go help env

usage: go env [-json] [-u] [-w] [var ...]

Env prints Go environment information.

By default env prints information as a shell script
(on Windows, a batch file). If one or more variable
names is given as arguments, env prints the value of
each named variable on its own line.

The -json flag prints the environment in JSON format
instead of as a shell script.

The -u flag requires one or more arguments and unsets
the default setting for the named environment variables,
if one has been set with 'go env -w'.

The -w flag requires one or more arguments of the
form NAME=VALUE and changes the default settings
of the named environment variables to the given values.

For more about environment variables, see 'go help environment'.

fix

update packages to use new APIs
更新软件包以使用新的 API

go help fix

usage: go fix [packages]

Fix runs the Go fix command on the packages named by the import paths.

For more about fix, see 'go doc cmd/fix'.
For more about specifying packages, see 'go help packages'.

To run fix with specific options, run 'go tool fix'.

See also: go fmt, go vet.

fmt

gofmt (reformat) package sources
gofmt（重新格式化）包源

go help fmt

usage: go fmt [-n] [-x] [packages]

Fmt runs the command 'gofmt -l -w' on the packages named
by the import paths. It prints the names of the files that are modified.

For more about gofmt, see 'go doc cmd/gofmt'.
For more about specifying packages, see 'go help packages'.

The -n flag prints commands that would be executed.
The -x flag prints commands as they are executed.

The -mod flag's value sets which module download mode
to use: readonly or vendor. See 'go help modules' for more.

To run gofmt with specific options, run gofmt itself.

See also: go fix, go vet.

generate

generate Go files by processing source
通过处理源生成 Go 文件

go help generate

usage: go generate [-run regexp] [-n] [-v] [-x] [build flags] [file.go... | packages]

Generate runs commands described by directives within existing
files. Those commands can run any process but the intent is to
create or update Go source files.

Go generate is never run automatically by go build, go get, go test,
and so on. It must be run explicitly.

Go generate scans the file for directives, which are lines of
the form,

	//go:generate command argument...

(note: no leading spaces and no space in "//go") where command
is the generator to be run, corresponding to an executable file
that can be run locally. It must either be in the shell path
(gofmt), a fully qualified path (/usr/you/bin/mytool), or a
command alias, described below.

Note that go generate does not parse the file, so lines that look
like directives in comments or multiline strings will be treated
as directives.

The arguments to the directive are space-separated tokens or
double-quoted strings passed to the generator as individual
arguments when it is run.

Quoted strings use Go syntax and are evaluated before execution; a
quoted string appears as a single argument to the generator.

To convey to humans and machine tools that code is generated,
generated source should have a line that matches the following
regular expression (in Go syntax):

	^// Code generated .* DO NOT EDIT\.$

This line must appear before the first non-comment, non-blank
text in the file.

Go generate sets several variables when it runs the generator:

	$GOARCH
		The execution architecture (arm, amd64, etc.)
	$GOOS
		The execution operating system (linux, windows, etc.)
	$GOFILE
		The base name of the file.
	$GOLINE
		The line number of the directive in the source file.
	$GOPACKAGE
		The name of the package of the file containing the directive.
	$DOLLAR
		A dollar sign.

Other than variable substitution and quoted-string evaluation, no
special processing such as "globbing" is performed on the command
line.

As a last step before running the command, any invocations of any
environment variables with alphanumeric names, such as $GOFILE or
$HOME, are expanded throughout the command line. The syntax for
variable expansion is $NAME on all operating systems. Due to the
order of evaluation, variables are expanded even inside quoted
strings. If the variable NAME is not set, $NAME expands to the
empty string.

A directive of the form,

	//go:generate -command xxx args...

specifies, for the remainder of this source file only, that the
string xxx represents the command identified by the arguments. This
can be used to create aliases or to handle multiword generators.
For example,

	//go:generate -command foo go tool foo

specifies that the command "foo" represents the generator
"go tool foo".

Generate processes packages in the order given on the command line,
one at a time. If the command line lists .go files from a single directory,
they are treated as a single package. Within a package, generate processes the
source files in a package in file name order, one at a time. Within
a source file, generate runs generators in the order they appear
in the file, one at a time. The go generate tool also sets the build
tag "generate" so that files may be examined by go generate but ignored
during build.

For packages with invalid code, generate processes only source files with a
valid package clause.

If any generator returns an error exit status, "go generate" skips
all further processing for that package.

The generator is run in the package's source directory.

Go generate accepts one specific flag:

	-run=""
		if non-empty, specifies a regular expression to select
		directives whose full original source text (excluding
		any trailing spaces and final newline) matches the
		expression.

It also accepts the standard build flags including -v, -n, and -x.
The -v flag prints the names of packages and files as they are
processed.
The -n flag prints commands that would be executed.
The -x flag prints commands as they are executed.

For more about build flags, see 'go help build'.

For more about specifying packages, see 'go help packages'.

get

add dependencies to current module and install them
将依赖项添加到当前模块并安装它们

go help get

usage: go get [-t] [-u] [-v] [build flags] [packages]

Get resolves its command-line arguments to packages at specific module versions,
updates go.mod to require those versions, and downloads source code into the
module cache.

To add a dependency for a package or upgrade it to its latest version:

	go get example.com/pkg

To upgrade or downgrade a package to a specific version:

	go get example.com/pkg@v1.2.3

To remove a dependency on a module and downgrade modules that require it:

	go get example.com/mod@none

See https://golang.org/ref/mod#go-get for details.

In earlier versions of Go, 'go get' was used to build and install packages.
Now, 'go get' is dedicated to adjusting dependencies in go.mod. 'go install'
may be used to build and install commands instead. When a version is specified,
'go install' runs in module-aware mode and ignores the go.mod file in the
current directory. For example:

	go install example.com/pkg@v1.2.3
	go install example.com/pkg@latest

See 'go help install' or https://golang.org/ref/mod#go-install for details.

'go get' accepts the following flags.

The -t flag instructs get to consider modules needed to build tests of
packages specified on the command line.

The -u flag instructs get to update modules providing dependencies
of packages named on the command line to use newer minor or patch
releases when available.

The -u=patch flag (not -u patch) also instructs get to update dependencies,
but changes the default to select patch releases.

When the -t and -u flags are used together, get will update
test dependencies as well.

The -x flag prints commands as they are executed. This is useful for
debugging version control commands when a module is downloaded directly
from a repository.

For more about modules, see https://golang.org/ref/mod.

For more about specifying packages, see 'go help packages'.

This text describes the behavior of get using modules to manage source
code and dependencies. If instead the go command is running in GOPATH
mode, the details of get's flags and effects change, as does 'go help get'.
See 'go help gopath-get'.

See also: go build, go install, go clean, go mod.

install

compile and install packages and dependencies
编译和安装包和依赖项

go help install

usage: go install [build flags] [packages]

Install compiles and installs the packages named by the import paths.

Executables are installed in the directory named by the GOBIN environment
variable, which defaults to $GOPATH/bin or $HOME/go/bin if the GOPATH
environment variable is not set. Executables in $GOROOT
are installed in $GOROOT/bin or $GOTOOLDIR instead of $GOBIN.

If the arguments have version suffixes (like @latest or @v1.0.0), "go install"
builds packages in module-aware mode, ignoring the go.mod file in the current
directory or any parent directory, if there is one. This is useful for
installing executables without affecting the dependencies of the main module.
To eliminate ambiguity about which module versions are used in the build, the
arguments must satisfy the following constraints:

- Arguments must be package paths or package patterns (with "..." wildcards).
They must not be standard packages (like fmt), meta-patterns (std, cmd,
all), or relative or absolute file paths.

- All arguments must have the same version suffix. Different queries are not
allowed, even if they refer to the same version.

- All arguments must refer to packages in the same module at the same version.

- No module is considered the "main" module. If the module containing
packages named on the command line has a go.mod file, it must not contain
directives (replace and exclude) that would cause it to be interpreted
differently than if it were the main module. The module must not require
a higher version of itself.

- Package path arguments must refer to main packages. Pattern arguments
will only match main packages.

If the arguments don't have version suffixes, "go install" may run in
module-aware mode or GOPATH mode, depending on the GO111MODULE environment
variable and the presence of a go.mod file. See 'go help modules' for details.
If module-aware mode is enabled, "go install" runs in the context of the main
module.

When module-aware mode is disabled, other packages are installed in the
directory $GOPATH/pkg/$GOOS_$GOARCH. When module-aware mode is enabled,
other packages are built and cached but not installed.

The -i flag installs the dependencies of the named packages as well.
The -i flag is deprecated. Compiled packages are cached automatically.

For more about the build flags, see 'go help build'.
For more about specifying packages, see 'go help packages'.

See also: go build, go get, go clean.

list

list packages or modules
列出包或模块

go help list

usage: go list [-f format] [-json] [-m] [list flags] [build flags] [packages]

List lists the named packages, one per line.
The most commonly-used flags are -f and -json, which control the form
of the output printed for each package. Other list flags, documented below,
control more specific details.

The default output shows the package import path:

    bytes
    encoding/json
    github.com/gorilla/mux
    golang.org/x/net/html

The -f flag specifies an alternate format for the list, using the
syntax of package template. The default output is equivalent
to -f '{{.ImportPath}}'. The struct being passed to the template is:

    type Package struct {
        Dir           string   // directory containing package sources
        ImportPath    string   // import path of package in dir
        ImportComment string   // path in import comment on package statement
        Name          string   // package name
        Doc           string   // package documentation string
        Target        string   // install path
        Shlib         string   // the shared library that contains this package (only set when -linkshared)
        Goroot        bool     // is this package in the Go root?
        Standard      bool     // is this package part of the standard Go library?
        Stale         bool     // would 'go install' do anything for this package?
        StaleReason   string   // explanation for Stale==true
        Root          string   // Go root or Go path dir containing this package
        ConflictDir   string   // this directory shadows Dir in $GOPATH
        BinaryOnly    bool     // binary-only package (no longer supported)
        ForTest       string   // package is only for use in named test
        Export        string   // file containing export data (when using -export)
        BuildID       string   // build ID of the compiled package (when using -export)
        Module        *Module  // info about package's containing module, if any (can be nil)
        Match         []string // command-line patterns matching this package
        DepOnly       bool     // package is only a dependency, not explicitly listed

        // Source files
        GoFiles         []string   // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
        CgoFiles        []string   // .go source files that import "C"
        CompiledGoFiles []string   // .go files presented to compiler (when using -compiled)
        IgnoredGoFiles  []string   // .go source files ignored due to build constraints
        IgnoredOtherFiles []string // non-.go source files ignored due to build constraints
        CFiles          []string   // .c source files
        CXXFiles        []string   // .cc, .cxx and .cpp source files
        MFiles          []string   // .m source files
        HFiles          []string   // .h, .hh, .hpp and .hxx source files
        FFiles          []string   // .f, .F, .for and .f90 Fortran source files
        SFiles          []string   // .s source files
        SwigFiles       []string   // .swig files
        SwigCXXFiles    []string   // .swigcxx files
        SysoFiles       []string   // .syso object files to add to archive
        TestGoFiles     []string   // _test.go files in package
        XTestGoFiles    []string   // _test.go files outside package

        // Embedded files
        EmbedPatterns      []string // //go:embed patterns
        EmbedFiles         []string // files matched by EmbedPatterns
        TestEmbedPatterns  []string // //go:embed patterns in TestGoFiles
        TestEmbedFiles     []string // files matched by TestEmbedPatterns
        XTestEmbedPatterns []string // //go:embed patterns in XTestGoFiles
        XTestEmbedFiles    []string // files matched by XTestEmbedPatterns

        // Cgo directives
        CgoCFLAGS    []string // cgo: flags for C compiler
        CgoCPPFLAGS  []string // cgo: flags for C preprocessor
        CgoCXXFLAGS  []string // cgo: flags for C++ compiler
        CgoFFLAGS    []string // cgo: flags for Fortran compiler
        CgoLDFLAGS   []string // cgo: flags for linker
        CgoPkgConfig []string // cgo: pkg-config names

        // Dependency information
        Imports      []string          // import paths used by this package
        ImportMap    map[string]string // map from source import to ImportPath (identity entries omitted)
        Deps         []string          // all (recursively) imported dependencies
        TestImports  []string          // imports from TestGoFiles
        XTestImports []string          // imports from XTestGoFiles

        // Error information
        Incomplete bool            // this package or a dependency has an error
        Error      *PackageError   // error loading package
        DepsErrors []*PackageError // errors loading dependencies
    }

Packages stored in vendor directories report an ImportPath that includes the
path to the vendor directory (for example, "d/vendor/p" instead of "p"),
so that the ImportPath uniquely identifies a given copy of a package.
The Imports, Deps, TestImports, and XTestImports lists also contain these
expanded import paths. See golang.org/s/go15vendor for more about vendoring.

The error information, if any, is

    type PackageError struct {
        ImportStack   []string // shortest path from package named on command line to this one
        Pos           string   // position of error (if present, file:line:col)
        Err           string   // the error itself
    }

The module information is a Module struct, defined in the discussion
of list -m below.

The template function "join" calls strings.Join.

The template function "context" returns the build context, defined as:

    type Context struct {
        GOARCH        string   // target architecture
        GOOS          string   // target operating system
        GOROOT        string   // Go root
        GOPATH        string   // Go path
        CgoEnabled    bool     // whether cgo can be used
        UseAllFiles   bool     // use files regardless of +build lines, file names
        Compiler      string   // compiler to assume when computing target paths
        BuildTags     []string // build constraints to match in +build lines
        ToolTags      []string // toolchain-specific build constraints
        ReleaseTags   []string // releases the current release is compatible with
        InstallSuffix string   // suffix to use in the name of the install dir
    }

For more information about the meaning of these fields see the documentation
for the go/build package's Context type.

The -json flag causes the package data to be printed in JSON format
instead of using the template format.

The -compiled flag causes list to set CompiledGoFiles to the Go source
files presented to the compiler. Typically this means that it repeats
the files listed in GoFiles and then also adds the Go code generated
by processing CgoFiles and SwigFiles. The Imports list contains the
union of all imports from both GoFiles and CompiledGoFiles.

The -deps flag causes list to iterate over not just the named packages
but also all their dependencies. It visits them in a depth-first post-order
traversal, so that a package is listed only after all its dependencies.
Packages not explicitly listed on the command line will have the DepOnly
field set to true.

The -e flag changes the handling of erroneous packages, those that
cannot be found or are malformed. By default, the list command
prints an error to standard error for each erroneous package and
omits the packages from consideration during the usual printing.
With the -e flag, the list command never prints errors to standard
error and instead processes the erroneous packages with the usual
printing. Erroneous packages will have a non-empty ImportPath and
a non-nil Error field; other information may or may not be missing
(zeroed).

The -export flag causes list to set the Export field to the name of a
file containing up-to-date export information for the given package.

The -find flag causes list to identify the named packages but not
resolve their dependencies: the Imports and Deps lists will be empty.

The -test flag causes list to report not only the named packages
but also their test binaries (for packages with tests), to convey to
source code analysis tools exactly how test binaries are constructed.
The reported import path for a test binary is the import path of
the package followed by a ".test" suffix, as in "math/rand.test".
When building a test, it is sometimes necessary to rebuild certain
dependencies specially for that test (most commonly the tested
package itself). The reported import path of a package recompiled
for a particular test binary is followed by a space and the name of
the test binary in brackets, as in "math/rand [math/rand.test]"
or "regexp [sort.test]". The ForTest field is also set to the name
of the package being tested ("math/rand" or "sort" in the previous
examples).

The Dir, Target, Shlib, Root, ConflictDir, and Export file paths
are all absolute paths.

By default, the lists GoFiles, CgoFiles, and so on hold names of files in Dir
(that is, paths relative to Dir, not absolute paths).
The generated files added when using the -compiled and -test flags
are absolute paths referring to cached copies of generated Go source files.
Although they are Go source files, the paths may not end in ".go".

The -m flag causes list to list modules instead of packages.

When listing modules, the -f flag still specifies a format template
applied to a Go struct, but now a Module struct:

    type Module struct {
        Path      string       // module path
        Version   string       // module version
        Versions  []string     // available module versions (with -versions)
        Replace   *Module      // replaced by this module
        Time      *time.Time   // time version was created
        Update    *Module      // available update, if any (with -u)
        Main      bool         // is this the main module?
        Indirect  bool         // is this module only an indirect dependency of main module?
        Dir       string       // directory holding files for this module, if any
        GoMod     string       // path to go.mod file used when loading this module, if any
        GoVersion string       // go version used in module
        Retracted string       // retraction information, if any (with -retracted or -u)
        Error     *ModuleError // error loading module
    }

    type ModuleError struct {
        Err string // the error itself
    }

The file GoMod refers to may be outside the module directory if the
module is in the module cache or if the -modfile flag is used.

The default output is to print the module path and then
information about the version and replacement if any.
For example, 'go list -m all' might print:

    my/main/module
    golang.org/x/text v0.3.0 => /tmp/text
    rsc.io/pdf v0.1.1

The Module struct has a String method that formats this
line of output, so that the default format is equivalent
to -f '{{.String}}'.

Note that when a module has been replaced, its Replace field
describes the replacement module, and its Dir field is set to
the replacement's source code, if present. (That is, if Replace
is non-nil, then Dir is set to Replace.Dir, with no access to
the replaced source code.)

The -u flag adds information about available upgrades.
When the latest version of a given module is newer than
the current one, list -u sets the Module's Update field
to information about the newer module. list -u will also set
the module's Retracted field if the current version is retracted.
The Module's String method indicates an available upgrade by
formatting the newer version in brackets after the current version.
If a version is retracted, the string "(retracted)" will follow it.
For example, 'go list -m -u all' might print:

    my/main/module
    golang.org/x/text v0.3.0 [v0.4.0] => /tmp/text
    rsc.io/pdf v0.1.1 (retracted) [v0.1.2]

(For tools, 'go list -m -u -json all' may be more convenient to parse.)

The -versions flag causes list to set the Module's Versions field
to a list of all known versions of that module, ordered according
to semantic versioning, earliest to latest. The flag also changes
the default output format to display the module path followed by the
space-separated version list.

The -retracted flag causes list to report information about retracted
module versions. When -retracted is used with -f or -json, the Retracted
field will be set to a string explaining why the version was retracted.
The string is taken from comments on the retract directive in the
module's go.mod file. When -retracted is used with -versions, retracted
versions are listed together with unretracted versions. The -retracted
flag may be used with or without -m.

The arguments to list -m are interpreted as a list of modules, not packages.
The main module is the module containing the current directory.
The active modules are the main module and its dependencies.
With no arguments, list -m shows the main module.
With arguments, list -m shows the modules specified by the arguments.
Any of the active modules can be specified by its module path.
The special pattern "all" specifies all the active modules, first the main
module and then dependencies sorted by module path.
A pattern containing "..." specifies the active modules whose
module paths match the pattern.
A query of the form path@version specifies the result of that query,
which is not limited to active modules.
See 'go help modules' for more about module queries.

The template function "module" takes a single string argument
that must be a module path or query and returns the specified
module as a Module struct. If an error occurs, the result will
be a Module struct with a non-nil Error field.

For more about build flags, see 'go help build'.

For more about specifying packages, see 'go help packages'.

For more about modules, see https://golang.org/ref/mod.

mod

module maintenance
模块维护

go help mod

Go mod provides access to operations on modules.

Note that support for modules is built into all the go commands,
not just 'go mod'. For example, day-to-day adding, removing, upgrading,
and downgrading of dependencies should be done using 'go get'.
See 'go help modules' for an overview of module functionality.

Usage:

	go mod <command> [arguments]

The commands are:

	download    download modules to local cache
	edit        edit go.mod from tools or scripts
	graph       print module requirement graph
	init        initialize new module in current directory
	tidy        add missing and remove unused modules
	vendor      make vendored copy of dependencies
	verify      verify dependencies have expected content
	why         explain why packages or modules are needed

Use "go help mod " for more information about a command.

download

download modules to local cache
下载模块到本地缓存

go help mod download

usage: go mod download [-x] [-json] [modules]

Download downloads the named modules, which can be module patterns selecting
dependencies of the main module or module queries of the form path@version.
With no arguments, download applies to all dependencies of the main module
(equivalent to 'go mod download all').

The go command will automatically download modules as needed during ordinary
execution. The "go mod download" command is useful mainly for pre-filling
the local cache or to compute the answers for a Go module proxy.

By default, download writes nothing to standard output. It may print progress
messages and errors to standard error.

The -json flag causes download to print a sequence of JSON objects
to standard output, describing each downloaded module (or failure),
corresponding to this Go struct:

    type Module struct {
        Path     string // module path
        Version  string // module version
        Error    string // error loading module
        Info     string // absolute path to cached .info file
        GoMod    string // absolute path to cached .mod file
        Zip      string // absolute path to cached .zip file
        Dir      string // absolute path to cached source root directory
        Sum      string // checksum for path, version (as in go.sum)
        GoModSum string // checksum for go.mod (as in go.sum)
    }

The -x flag causes download to print the commands download executes.

See https://golang.org/ref/mod#go-mod-download for more about 'go mod download'.

See https://golang.org/ref/mod#version-queries for more about version queries.

edit

edit go.mod from tools or scripts
从工具或脚本编辑 go.mod

go help mod edit

usage: go mod edit [editing flags] [-fmt|-print|-json] [go.mod]

Edit provides a command-line interface for editing go.mod,
for use primarily by tools or scripts. It reads only go.mod;
it does not look up information about the modules involved.
By default, edit reads and writes the go.mod file of the main module,
but a different target file can be specified after the editing flags.

The editing flags specify a sequence of editing operations.

The -fmt flag reformats the go.mod file without making other changes.
This reformatting is also implied by any other modifications that use or
rewrite the go.mod file. The only time this flag is needed is if no other
flags are specified, as in 'go mod edit -fmt'.

The -module flag changes the module's path (the go.mod file's module line).

The -require=path@version and -droprequire=path flags
add and drop a requirement on the given module path and version.
Note that -require overrides any existing requirements on path.
These flags are mainly for tools that understand the module graph.
Users should prefer 'go get path@version' or 'go get path@none',
which make other go.mod adjustments as needed to satisfy
constraints imposed by other modules.

The -exclude=path@version and -dropexclude=path@version flags
add and drop an exclusion for the given module path and version.
Note that -exclude=path@version is a no-op if that exclusion already exists.

The -replace=old[@v]=new[@v] flag adds a replacement of the given
module path and version pair. If the @v in old@v is omitted, a
replacement without a version on the left side is added, which applies
to all versions of the old module path. If the @v in new@v is omitted,
the new path should be a local module root directory, not a module
path. Note that -replace overrides any redundant replacements for old[@v],
so omitting @v will drop existing replacements for specific versions.

The -dropreplace=old[@v] flag drops a replacement of the given
module path and version pair. If the @v is omitted, a replacement without
a version on the left side is dropped.

The -retract=version and -dropretract=version flags add and drop a
retraction on the given version. The version may be a single version
like "v1.2.3" or a closed interval like "[v1.1.0,v1.1.9]". Note that
-retract=version is a no-op if that retraction already exists.

The -require, -droprequire, -exclude, -dropexclude, -replace,
-dropreplace, -retract, and -dropretract editing flags may be repeated,
and the changes are applied in the order given.

The -go=version flag sets the expected Go language version.

The -print flag prints the final go.mod in its text format instead of
writing it back to go.mod.

The -json flag prints the final go.mod file in JSON format instead of
writing it back to go.mod. The JSON output corresponds to these Go types:

	type Module struct {
		Path    string
		Version string
	}

	type GoMod struct {
		Module  ModPath
		Go      string
		Require []Require
		Exclude []Module
		Replace []Replace
		Retract []Retract
	}

	type ModPath struct {
		Path       string
		Deprecated string
	}

	type Require struct {
		Path string
		Version string
		Indirect bool
	}

	type Replace struct {
		Old Module
		New Module
	}

	type Retract struct {
		Low       string
		High      string
		Rationale string
	}

Retract entries representing a single version (not an interval) will have
the "Low" and "High" fields set to the same value.

Note that this only describes the go.mod file itself, not other modules
referred to indirectly. For the full set of modules available to a build,
use 'go list -m -json all'.

See https://golang.org/ref/mod#go-mod-edit for more about 'go mod edit'.

graph

print module requirement graph
打印模块需求图

go help mod graph

usage: go mod graph [-go=version]

Graph prints the module requirement graph (with replacements applied)
in text form. Each line in the output has two space-separated fields: a module
and one of its requirements. Each module is identified as a string of the form
path@version, except for the main module, which has no @version suffix.

The -go flag causes graph to report the module graph as loaded by the
given Go version, instead of the version indicated by the 'go' directive
in the go.mod file.

See https://golang.org/ref/mod#go-mod-graph for more about 'go mod graph'.

init

initialize new module in current directory
在当前目录初始化新模块

go help mod init

usage: go mod init [module-path]

Init initializes and writes a new go.mod file in the current directory, in
effect creating a new module rooted at the current directory. The go.mod file
must not already exist.

Init accepts one optional argument, the module path for the new module. If the
module path argument is omitted, init will attempt to infer the module path
using import comments in .go files, vendoring tool configuration files (like
Gopkg.lock), and the current directory (if in GOPATH).

If a configuration file for a vendoring tool is present, init will attempt to
import module requirements from it.

See https://golang.org/ref/mod#go-mod-init for more about 'go mod init'.

tidy

add missing and remove unused modules
添加缺失和删除未使用的模块

go help mod tidy

usage: go mod tidy [-e] [-v] [-go=version] [-compat=version]

Tidy makes sure go.mod matches the source code in the module.
It adds any missing modules necessary to build the current module's
packages and dependencies, and it removes unused modules that
don't provide any relevant packages. It also adds any missing entries
to go.sum and removes any unnecessary ones.

The -v flag causes tidy to print information about removed modules
to standard error.

The -e flag causes tidy to attempt to proceed despite errors
encountered while loading packages.

The -go flag causes tidy to update the 'go' directive in the go.mod
file to the given version, which may change which module dependencies
are retained as explicit requirements in the go.mod file.
(Go versions 1.17 and higher retain more requirements in order to
support lazy module loading.)

The -compat flag preserves any additional checksums needed for the
'go' command from the indicated major Go release to successfully load
the module graph, and causes tidy to error out if that version of the
'go' command would load any imported package from a different module
version. By default, tidy acts as if the -compat flag were set to the
version prior to the one indicated by the 'go' directive in the go.mod
file.

See https://golang.org/ref/mod#go-mod-tidy for more about 'go mod tidy'.

vendor

make vendored copy of dependencies
制作依赖项的 vendored 副本

go help mod vendor

usage: go mod vendor [-e] [-v]

Vendor resets the main module's vendor directory to include all packages
needed to build and test all the main module's packages.
It does not include test code for vendored packages.

The -v flag causes vendor to print the names of vendored
modules and packages to standard error.

The -e flag causes vendor to attempt to proceed despite errors
encountered while loading packages.

See https://golang.org/ref/mod#go-mod-vendor for more about 'go mod vendor'.

verify

verify dependencies have expected content
验证依赖项是否具有预期内容

go help mod verify

usage: go mod verify

Verify checks that the dependencies of the current module,
which are stored in a local downloaded source cache, have not been
modified since being downloaded. If all the modules are unmodified,
verify prints "all modules verified." Otherwise it reports which
modules have been changed and causes 'go mod' to exit with a
non-zero status.

See https://golang.org/ref/mod#go-mod-verify for more about 'go mod verify'.

why

explain why packages or modules are needed
解释为什么需要包或模块

go help mod why

usage: go mod why [-m] [-vendor] packages...

Why shows a shortest path in the import graph from the main module to
each of the listed packages. If the -m flag is given, why treats the
arguments as a list of modules and finds a path to any package in each
of the modules.

By default, why queries the graph of packages matched by "go list all",
which includes tests for reachable packages. The -vendor flag causes why
to exclude tests of dependencies.

The output is a sequence of stanzas, one for each package or module
name on the command line, separated by blank lines. Each stanza begins
with a comment line "# package" or "# module" giving the target
package or module. Subsequent lines give a path through the import
graph, one package per line. If the package or module is not
referenced from the main module, the stanza will display a single
parenthesized note indicating that fact.

For example:

	$ go mod why golang.org/x/text/language golang.org/x/text/encoding
	# golang.org/x/text/language
	rsc.io/quote
	rsc.io/sampler
	golang.org/x/text/language

	# golang.org/x/text/encoding
	(main module does not need package golang.org/x/text/encoding)
	$

See https://golang.org/ref/mod#go-mod-why for more about 'go mod why'.

run

compile and run Go program
编译并运行 Go 程序

go help run

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

Run compiles and runs the named main Go package.
Typically the package is specified as a list of .go source files from a single
directory, but it may also be an import path, file system path, or pattern
matching a single known package, as in 'go run .' or 'go run my/cmd'.

If the package argument has a version suffix (like @latest or @v1.0.0),
"go run" builds the program in module-aware mode, ignoring the go.mod file in
the current directory or any parent directory, if there is one. This is useful
for running programs without affecting the dependencies of the main module.

If the package argument doesn't have a version suffix, "go run" may run in
module-aware mode or GOPATH mode, depending on the GO111MODULE environment
variable and the presence of a go.mod file. See 'go help modules' for details.
If module-aware mode is enabled, "go run" runs in the context of the main
module.

By default, 'go run' runs the compiled binary directly: 'a.out arguments...'.
If the -exec flag is given, 'go run' invokes the binary using xprog:
	'xprog a.out arguments...'.
If the -exec flag is not given, GOOS or GOARCH is different from the system
default, and a program named go_$GOOS_$GOARCH_exec can be found
on the current search path, 'go run' invokes the binary using that program,
for example 'go_js_wasm_exec a.out arguments...'. This allows execution of
cross-compiled programs when a simulator or other execution method is
available.

The exit status of Run is not the exit status of the compiled binary.

For more about build flags, see 'go help build'.
For more about specifying packages, see 'go help packages'.

See also: go build.

test

test packages
测试包

go help test

usage: go test [build/test flags] [packages] [build/test flags & test binary flags]

'Go test' automates testing the packages named by the import paths.
It prints a summary of the test results in the format:

	ok   archive/tar   0.011s
	FAIL archive/zip   0.022s
	ok   compress/gzip 0.033s
	...

followed by detailed output for each failed package.

'Go test' recompiles each package along with any files with names matching
the file pattern "*_test.go".
These additional files can contain test functions, benchmark functions, and
example functions. See 'go help testfunc' for more.
Each listed package causes the execution of a separate test binary.
Files whose names begin with "_" (including "_test.go") or "." are ignored.

Test files that declare a package with the suffix "_test" will be compiled as a
separate package, and then linked and run with the main test binary.

The go tool will ignore a directory named "testdata", making it available
to hold ancillary data needed by the tests.

As part of building a test binary, go test runs go vet on the package
and its test source files to identify significant problems. If go vet
finds any problems, go test reports those and does not run the test
binary. Only a high-confidence subset of the default go vet checks are
used. That subset is: 'atomic', 'bool', 'buildtags', 'errorsas',
'ifaceassert', 'nilfunc', 'printf', and 'stringintconv'. You can see
the documentation for these and other vet tests via "go doc cmd/vet".
To disable the running of go vet, use the -vet=off flag.

All test output and summary lines are printed to the go command's
standard output, even if the test printed them to its own standard
error. (The go command's standard error is reserved for printing
errors building the tests.)

Go test runs in two different modes:

The first, called local directory mode, occurs when go test is
invoked with no package arguments (for example, 'go test' or 'go
test -v'). In this mode, go test compiles the package sources and
tests found in the current directory and then runs the resulting
test binary. In this mode, caching (discussed below) is disabled.
After the package test finishes, go test prints a summary line
showing the test status ('ok' or 'FAIL'), package name, and elapsed
time.

The second, called package list mode, occurs when go test is invoked
with explicit package arguments (for example 'go test math', 'go
test ./...', and even 'go test .'). In this mode, go test compiles
and tests each of the packages listed on the command line. If a
package test passes, go test prints only the final 'ok' summary
line. If a package test fails, go test prints the full test output.
If invoked with the -bench or -v flag, go test prints the full
output even for passing package tests, in order to display the
requested benchmark results or verbose logging. After the package
tests for all of the listed packages finish, and their output is
printed, go test prints a final 'FAIL' status if any package test
has failed.

In package list mode only, go test caches successful package test
results to avoid unnecessary repeated running of tests. When the
result of a test can be recovered from the cache, go test will
redisplay the previous output instead of running the test binary
again. When this happens, go test prints '(cached)' in place of the
elapsed time in the summary line.

The rule for a match in the cache is that the run involves the same
test binary and the flags on the command line come entirely from a
restricted set of 'cacheable' test flags, defined as -benchtime, -cpu,
-list, -parallel, -run, -short, and -v. If a run of go test has any test
or non-test flags outside this set, the result is not cached. To
disable test caching, use any test flag or argument other than the
cacheable flags. The idiomatic way to disable test caching explicitly
is to use -count=1. Tests that open files within the package's source
root (usually $GOPATH) or that consult environment variables only
match future runs in which the files and environment variables are unchanged.
A cached test result is treated as executing in no time at all,
so a successful package test result will be cached and reused
regardless of -timeout setting.

In addition to the build flags, the flags handled by 'go test' itself are:

	-args
	    Pass the remainder of the command line (everything after -args)
	    to the test binary, uninterpreted and unchanged.
	    Because this flag consumes the remainder of the command line,
	    the package list (if present) must appear before this flag.

	-c
	    Compile the test binary to pkg.test but do not run it
	    (where pkg is the last element of the package's import path).
	    The file name can be changed with the -o flag.

	-exec xprog
	    Run the test binary using xprog. The behavior is the same as
	    in 'go run'. See 'go help run' for details.

	-i
	    Install packages that are dependencies of the test.
	    Do not run the test.
	    The -i flag is deprecated. Compiled packages are cached automatically.

	-json
	    Convert test output to JSON suitable for automated processing.
	    See 'go doc test2json' for the encoding details.

	-o file
	    Compile the test binary to the named file.
	    The test still runs (unless -c or -i is specified).

The test binary also accepts flags that control execution of the test; these
flags are also accessible by 'go test'. See 'go help testflag' for details.

For more about build flags, see 'go help build'.
For more about specifying packages, see 'go help packages'.

See also: go build, go vet.

tool

run specified go tool
运行指定的 go 工具

go help tool

usage: go tool [-n] command [args...]

Tool runs the go tool command identified by the arguments.
With no arguments it prints the list of known tools.

The -n flag causes tool to print the command that would be
executed but not execute it.

For more about each tool command, see 'go doc cmd/<command>'.

version

print Go version
打印 Go 版本

go help version

usage: go version [-m] [-v] [file ...]

Version prints the build information for Go executables.

Go version reports the Go version used to build each of the named
executable files.

If no files are named on the command line, go version prints its own
version information.

If a directory is named, go version walks that directory, recursively,
looking for recognized Go binaries and reporting their versions.
By default, go version does not report unrecognized files found
during a directory scan. The -v flag causes it to report unrecognized files.

The -m flag causes go version to print each executable's embedded
module version information, when available. In the output, the module
information consists of multiple lines following the version line, each
indented by a leading tab character.

See also: go doc runtime/debug.BuildInfo.

vet

report likely mistakes in packages
报告包中可能出现的错误

go help vet

usage: go vet [-n] [-x] [-vettool prog] [build flags] [vet flags] [packages]

Vet runs the Go vet command on the packages named by the import paths.

For more about vet and its flags, see 'go doc cmd/vet'.
For more about specifying packages, see 'go help packages'.
For a list of checkers and their flags, see 'go tool vet help'.
For details of a specific checker such as 'printf', see 'go tool vet help printf'.

The -n flag prints commands that would be executed.
The -x flag prints commands as they are executed.

The -vettool=prog flag selects a different analysis tool with alternative
or additional checks.
For example, the 'shadow' analyzer can be built and run using these commands:

  go install golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow
  go vet -vettool=$(which shadow)

The build flags supported by go vet are those that control package resolution
and execution, such as -n, -x, -v, -tags, and -toolexec.
For more about these flags, see 'go help build'.

See also: go fmt, go fix.