add -F cmd line option

README.md

@@ -9,21 +9,22 @@ Binaries for Windows, macOS, Linux and FreeBSD are provided on the
 * For help, run `chars -h`
 
 ```
-chars v2.2.0
+chars v2.3.0
 Determine the end-of-line format, tabs, bom, and nul
 https://github.com/jftuga/chars
 
 Usage:
 chars [filename or file-glob 1] [filename or file-glob 2] ...
-  -b    examine binary files
+  -F	when used with -f, only display a list of failed files (one per line
+  -b	examine binary files
   -e string
         exclude based on regular expression; use .* instead of *
   -f string
         fail with OS exit code=100 if any of the included characters exist; ex: -f crlf,nul,bom8
-  -j    output results in JSON format; can't be used with -l
+  -j	output results in JSON format; can't be used with -l
   -l int
         shorten files names to a maximum of this length
-  -v    display version and then exit
+  -v	display version and then exit
 
 Notes:
 Use - to read a file from STDIN
@@ -113,6 +114,18 @@ $ chars -f lf,tab /etc/group ; echo $?
 ```
 
 ## Example 5
+* Fail when certain characters are detected, with `-f`
+* Only output failed file names, with `-F`
+
+```shell
+$ chars -f lf,tab -F /etc/gr* ; echo $?
+/etc/group
+/etc/group.bak
+
+100
+```
+
+## Example 6
 
 * Output to JSON, with `-j`
 * Use `-e` to exclude and filenames starting with `go`, such as `go.mod` and `go.sum`

chars.go

@@ -30,7 +30,7 @@ import (
 const PgmName string = "chars"
 const PgmDesc string = "Determine the end-of-line format, tabs, bom, and nul"
 const PgmUrl string = "https://github.com/jftuga/chars"
-const PgmVersion string = "2.2.0"
+const PgmVersion string = "2.3.0"
 const BlockSize int = 4096
 
 type SpecialChars struct {
@@ -42,6 +42,7 @@ type SpecialChars struct {
 	Bom16     uint64 `json:"bom16"`
 	Nul       uint64 `json:"nul"`
 	BytesRead uint64 `json:"bytesRead"`
+	Failure   bool   `json:"failure"`
 }
 
 type CharsError struct {
@@ -201,6 +202,19 @@ func OutputTextTable(allStats []SpecialChars, maxLength int) error {
 	return w.Flush()
 }
 
+// OutputFailedFileList - only display a list of file names that have failed when using -F cmd line option
+func OutputFailedFileList(allStats []SpecialChars) {
+	if len(allStats) == 0 {
+		return
+	}
+
+	for _, stat := range allStats {
+		if stat.Failure {
+			_, _ = fmt.Println(stat.Filename)
+		}
+	}
+}
+
 // GetJSON - return results JSON format
 func GetJSON(allStats []SpecialChars) string {
 	j, err := json.MarshalIndent(allStats, "", "    ")
@@ -298,11 +312,12 @@ func ProcessStdin(allStats *[]SpecialChars, examineBinary bool, fail string) (ui
 
 // GetFailures - parse as comma-delimited list and return the number of characters in the given character list
 func GetFailures(commaList string, allStats *[]SpecialChars) uint64 {
-	var failed uint64
+	var failed, totalFailures uint64
 
 	classes := strings.Split(strings.ToLower(commaList), ",")
-	for _, class := range classes {
-		for _, entry := range *allStats {
+	for i, entry := range *allStats {
+		failed = 0
+		for _, class := range classes {
 			switch class {
 			case "crlf":
 				failed += entry.Crlf
@@ -320,6 +335,11 @@ func GetFailures(commaList string, allStats *[]SpecialChars) uint64 {
 				fmt.Fprintf(os.Stderr, "Unknown character passed to -f: %s\n", class)
 			}
 		}
+
+		if failed > 0 {
+			totalFailures += failed
+			(*allStats)[i].Failure = true
+		}
 	}
-	return failed
+	return totalFailures
 }

cmd/chars/cmd.go

@@ -43,6 +43,7 @@ func main() {
 	argsJSON := flag.Bool("j", false, "output results in JSON format; can't be used with -l")
 	argsVersion := flag.Bool("v", false, "display version and then exit")
 	argsFail := flag.String("f", "", "fail with OS exit code=100 if any of the included characters exist; ex: -f crlf,nul,bom8")
+	argsFailedFileList := flag.Bool("F", false, "when used with -f, only display a list of failed files (one per line")
 
 	flag.Usage = Usage
 	flag.Parse()
@@ -95,6 +96,8 @@ func main() {
 		if err != nil {
 			os.Exit(4)
 		}
+	} else if *argsFailedFileList && len(*argsFail) > 0 && failed > 0 {
+		chars.OutputFailedFileList(allStats)
 	} else {
 		err := chars.OutputTextTable(allStats, *argsMaxLength)
 		if err != nil {