Fix shell escaping for fish

Fix #3224

src/terminal_unix.go

@@ -11,6 +11,20 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+var escaper *strings.Replacer
+
+func init() {
+	tokens := strings.Split(os.Getenv("SHELL"), "/")
+	if tokens[len(tokens)-1] == "fish" {
+		// https://fishshell.com/docs/current/language.html#quotes
+		// > The only meaningful escape sequences in single quotes are \', which
+		// > escapes a single quote and \\, which escapes the backslash symbol.
+		escaper = strings.NewReplacer("\\", "\\\\", "'", "\\'")
+	} else {
+		escaper = strings.NewReplacer("'", "'\\''")
+	}
+}
+
 func notifyOnResize(resizeChan chan<- os.Signal) {
 	signal.Notify(resizeChan, syscall.SIGWINCH)
 }
@@ -29,5 +43,5 @@ func notifyOnCont(resizeChan chan<- os.Signal) {
 }
 
 func quoteEntry(entry string) string {
-	return "'" + strings.Replace(entry, "'", "'\\''", -1) + "'"
+	return "'" + escaper.Replace(entry) + "'"
 }