Adds a new -l, --log option.

snapraid.d

@@ -8,7 +8,7 @@ Synopsis
 	:	[-N, --find-by-name]
 	:	[-Z, --force-zero] [-E, --force-empty]
 	:	[-s, --start BLKSTART] [-t, --count BLKCOUNT]
-	:	[-v, --verbose]
+	:	[-v, --verbose] [-l, --log FILE]
 	:	sync|pool|diff|dup|check|fix
 
 	:snapraid [-V, --version] [-h, --help]
@@ -372,6 +372,15 @@ Options
 		Process only the specified number of blocks.
 		It's present mainly for advanced manual recovering.
 
+	-l, --log FILE
+		Outputs a detailed log to the specified file.
+		It contains the exact specification of which block of
+		any file is not recoverable and why.
+		You can use the special files "1" and "2" to output
+		to stdout and stderr.
+		If this option is not specified, no detailed log is
+		generated.
+
 	-v, --verbose
 		Prints more information in the processing.