Go Systems Programming

Reading from standard input

The first thing that you need to know in order to develop Go applications that support Unix pipes is how to read from standard input.

The developed program is named readSTDIN.go and will be presented in three parts.

The first part of the program is the expected preamble:

package main 
 
import ( 
   "bufio" 
   "fmt" 
   "os" 
) 

The second part of readSTDIN.go has the following Go code:

func main() { 
   filename := "" 
   var f *os.File 
   arguments := os.Args 
   if len(arguments) == 1 { 
         f = os.Stdin 
   } else { 
         filename = arguments[1] 
         fileHandler, err := os.Open(filename) 
         if err != nil { 
               fmt.Printf("error opening %s: %s", filename, err) 
               os.Exit(1) 
         } 
         f = fileHandler 
   } 
   defer f.Close() 

Here, you resolve whether you have an actual file to process, ...