cmd/app: omit hidden files

This avoids vim swap files breaking scripts.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/app/app.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"fmt"
 	"io"
+	"os"
 	"strconv"
 	"strings"
 
@@ -335,3 +336,19 @@ func parse(
 
 	return &c, nil
 }
+
+// list prints names of non-hidden entries in pathname.
+func list(pathname *check.Absolute, dir bool) error {
+	dents, err := os.ReadDir(pathname.String())
+	if err != nil {
+		return err
+	}
+	for _, dent := range dents {
+		name := dent.Name()
+		if (dent.IsDir() != dir) || (len(name) > 0 && name[0] == '.') {
+			continue
+		}
+		fmt.Println(dent.Name())
+	}
+	return nil
+}