Add @file flag parsing syntax

main.go

@@ -5,6 +5,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"strings"
 
 	"github.com/boyter/scc/v3/processor"
 	"github.com/spf13/cobra"
@@ -16,6 +17,23 @@ func main() {
 	//pprof.StartCPUProfile(f)
 	//defer pprof.StopCPUProfile()
 
+	if len(os.Args) == 2 && strings.HasPrefix(os.Args[1], "@") {
+		// handle "scc @flags.txt" syntax
+		filepath := strings.TrimPrefix(os.Args[1], "@")
+		b, err := os.ReadFile(filepath)
+		if err != nil {
+			fmt.Printf("Error reading flags from a file: %s\n", err)
+			os.Exit(1)
+		}
+
+		args := strings.Split(string(b), "\n")
+		var newArgs []string
+		for _, x := range args {
+			newArgs = append(newArgs, strings.TrimSpace(x))
+		}
+		os.Args = append([]string{os.Args[0]}, newArgs...)
+	}
+
 	rootCmd := &cobra.Command{
 		Use:     "scc [flags] [files or directories]",
 		Short:   "scc [files or directories]",

test-all.sh

@@ -1,5 +1,8 @@
 #!/bin/bash
 
+# make sure this script can be executed from any dir
+cd $(dirname $0)
+
 GREEN='\033[1;32m'
 RED='\033[0;31m'
 NC='\033[0m'
@@ -28,6 +31,24 @@ echo '```' > LANGUAGES.md
 ./scc --languages >> LANGUAGES.md
 echo '```' >> LANGUAGES.md
 
+
+echo "Running with @file flag parsing syntax"
+# include \n, \r\n and no line terminators
+echo -e "go.mod\ngo.sum\r\nLICENSE" > flags.txt
+if ./scc @flags.txt ; then
+    echo -e "${GREEN}PASSED @file flag syntax"
+    # post processing
+    rm flags.txt
+else
+    echo -e "${RED}======================================================="
+    echo -e "FAILED Should handle @file flag parsing syntax"
+    echo -e "=======================================================${NC}"
+    # post processing
+    rm flags.txt
+    exit
+fi
+
+
 echo "Building HTML report..."
 
 ./scc --format html -o SCC-OUTPUT-REPORT.html