// Spawn a process
func (s *Spawner) spawn(i int) {
s.procs <- i
cmd := s.cmds[i]
fmt.Fprintf(os.Stderr, "Spawning: %s\n", cmd)
_, err := exec.Command("bash", "-c", cmd).Output()
if err != nil {
msg := fmt.Sprintf("Spawner could not run command: %s, %s\n", cmd, err.Error())
s.errs[i] = msg
alert.Cerr(msg)
}
_ = <-s.procs
s.alive.Done()
}
func main() {
args := args.New(os.Args)
// Help
if args.IsOn("h") {
fmt.Fprintf(os.Stderr, usage())
os.Exit(0)
}
// Read Columns
var cols []uint32
for a := 1; a < args.Size(); a++ {
col := lax.ParseUint32(args.Get(a))
if col <= 0 {
alert.Cerr("Columns start at 1")
os.Exit(1)
}
cols = append(cols, col-1)
}
// Skip Header Lines (Optional)
var skip int
// Option: -s (Skip One Header Line)
if args.IsOn("s") {
skip = 1
}
// Option: -s=N (Skip N Header Lines)
if args.HasOpt("s") {
skip = args.GetOptI("s")
}
// Read Stdin
scanner := bufio.NewScanner(os.Stdin)
for scanner.Scan() {
line := scanner.Text()
// Skip Header
if skip > 0 {
skip--
continue
}
var tokens []string
if args.IsOn("space") {
// Split By Whitespace
tokens = strings.Fields(line)
} else {
// Split By Comma
tokens = strings.Split(line, ",")
}
// Display Columns
for i, col := range cols {
if col < uint32(len(tokens)) {
if i > 0 {
fmt.Printf(" ")
}
fmt.Printf("%s", tokens[col])
}
}
fmt.Println()
}
}