Created
May 31, 2017 13:23
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| package main | |
| import ( | |
| "bufio" | |
| "os" | |
| "io" | |
| "log" | |
| "fmt" | |
| "flag" | |
| "os/signal" | |
| "syscall" | |
| ) | |
| var nthByte int | |
| var replacement int | |
| var buffLines int | |
| func main() { | |
| initFlags() | |
| interrupt() | |
| r := bufio.NewReaderSize(os.Stdin, buffLines*nthByte) | |
| buf := make([]byte, 0, nthByte) | |
| replacementByte := byte(replacement) | |
| for { | |
| n, err := r.Read(buf[:cap(buf)]) | |
| buf = buf[:n] | |
| if n < nthByte { | |
| m, err2 := r.Read(buf[n:cap(buf)]) | |
| err = err2 | |
| buf = buf[:m+n] | |
| } | |
| if n == 0 { | |
| if err == nil { | |
| continue | |
| } | |
| if err == io.EOF { | |
| break | |
| } | |
| log.Fatal(err) | |
| } | |
| buf[nthByte-1] = replacementByte | |
| fmt.Print(string(buf)) | |
| } | |
| } | |
| func interrupt() { | |
| c := make(chan os.Signal, 2) | |
| signal.Notify(c, os.Interrupt, syscall.SIGTERM) | |
| go func() { | |
| <-c | |
| os.Exit(1) | |
| }() | |
| } | |
| func initFlags() { | |
| flag.IntVar(&nthByte, "n", 136, "Each nth byte will be replaced in stream") | |
| flag.IntVar(&replacement, "r", 10, "Replacement decimal") | |
| flag.IntVar(&buffLines, "b", 100, "Number of lines read to buffer") | |
| flag.Parse() | |
| } |
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