golang implement programs using a command-line help

By flagpackage we can easily achieve the program's command-line parameter markers,
then we look at how to use the Help command-line program,
usually parameter flag -hor --helpform to use.

Automatically generated using the help

We only need to declare other parameter markers, and execution resolution, flagthe package will help us to automatically generate use help.

// main.go
 // output number 2, a large number of output 
Package main 

Import ( 
    " In Flag " 
    " FMT " 
    " Math " 
) 

FUNC main () { 
    firstFlag: = flag.Float64 ( " First " , 0 , " The first number " ) 
    secondFlag: = flag.Float64 ( " sECOND " , 0 , " second number " ) 
    flag.Parse () 
    max: = math.max (firstFlag *, * secondFlag)  
    FMT.Print(max)
}

 

Compiled after the implementation of a look:

E: \ GOPATH \ the src \ max> max.exe - Help 
the Usage of max.exe:
   -first a float 
        first number
   -Second a float 
        second number 

E: \ GOPATH \ the src \ max > = max.exe -first . 5 = -Second 66 
66

 

Custom Use Help

Maybe you do not like or are not satisfied with the automatically generated using the help, then you can also try using a custom help. We use the same flagpackage, but here rewritten flag.Usageto implement custom use help.

// main.go 
Package main 

Import ( 
    " In Flag " 
    " FMT " 
) 

const Help = ` 
Program Name: max 
Description: The number of output 2, output of a large number. 
Example: 
. 1 . Test - Help
 2 max = -first. . 5 -Second = 66 
` 

FUNC main () { 
    flag.Usage = FUNC () { 
        fmt.Print (help) 
    } 
    flag.Parse () 
    // here only used to help implement. 
}

 

Compiled after the implementation of a look:

E: \ GOPATH \ the src \ max> max.exe - Help 

Program Name: max 
Description: The number of output 2, output of a large number. 
Example: 
. 1 . Test - Help
 2 . -First = max . 5 -Second = 66

 

reference

• CLI: command-line application developed using the Go