added err and lookup

lib.go

@@ -390,14 +390,18 @@ func ExecStr(str string, opts ...*Opts) (string, error) {
 
 	cmdwd := opt.Wd
 
-	prepCmd := func(l Line) *exec.Cmd {
-		cmd := exec.Command(l.Tokens[0], l.Tokens[1:]...)
+	prepCmd := func(l Line) (*exec.Cmd, error) {
+		str, err := exec.LookPath(l.Tokens[0])
+		if err != nil {
+			return nil, err
+		}
+		cmd := exec.Command(str, l.Tokens[1:]...)
 		cmd.Stdout = log.Writer()
 		cmd.Stderr = log.Writer()
 		cmd.Dir = cmdwd
 		opt.SetupProc(cmd)
 		ret = append(ret, cmd)
-		return cmd
+		return cmd, nil
 	}
 
 	lines, err := Lines(str)
@@ -423,7 +427,10 @@ func ExecStr(str string, opts ...*Opts) (string, error) {
 			log.Printf("CMDWD NOW IS: %s", cmdwd)
 			continue
 		case LINETYPE_SERIAL, LINETYPE_PARALLEL:
-			cmd := prepCmd(l)
+			cmd, err := prepCmd(l)
+			if err != nil {
+				return "", err
+			}
 			if opt.Debug {
 				log.Printf("Running %s from dir %s with params %v", cmd.Path, cmd.Dir, cmd.Args)
 			}