diff --git a/b2/boom.c b/b2/boom.c
index 5b9257b..1bf5e1a 100644
--- a/b2/boom.c
+++ b/b2/boom.c
@@ -75,7 +75,7 @@ static void do_substitutions(void)
 static void usage(const char *name)
 {
 	fprintf(stderr,
-"usage: %s file [[-type] file ...] [(-q|-Q) var=value ...] ...\n\n"
+"usage: %s file [[-N name] [-type] file ...] [(-q|-Q) var=value ...] ...\n\n"
 "  file types:\n"
 "  -c  characteristics\n"
 "  -i  inventory\n"
@@ -84,6 +84,8 @@ static void usage(const char *name)
 "  -s  substitutions\n"
 "  -b  KiCad eeschema BOM\n"
 "  -X  symbols (BOM supplement)\n"
+"  other options:\n"
+"  -N name           for the next file, override the name in diagnostics\n"
 "  -q var=value ...  run substitutions with the specified inputs\n"
 "  -Q var=value ...  run substitutions and then do parametric search\n"
     , name);
@@ -99,7 +101,10 @@ int main(int argc, char **argv)
 	dollar = unique("$");
 	for (i = 1; i != argc; i++) {
 		if (*argv[i] == '-') {
-			if (!strcmp(argv[i], "-c"))
+			if (!strcmp(argv[i], "-N")) {
+				i++;
+				file_name_override = argv[i];
+			} else if (!strcmp(argv[i], "-c"))
 				process = parse_characteristics;
 			else if (!strcmp(argv[i], "-i"))
 				process = parse_inventory;
diff --git a/b2/lang.h b/b2/lang.h
index fa1256e..869ce20 100644
--- a/b2/lang.h
+++ b/b2/lang.h
@@ -22,6 +22,8 @@ extern const char *dollar; /* "$" */
 extern struct action hierarchy;
 extern struct subst *substitutions;
 
+extern const char *file_name_override;
+
 void parse_hierarchy(const char *name);
 void parse_characteristics(const char *name);
 void parse_inventory(const char *name);
diff --git a/b2/lang.l b/b2/lang.l
index abb5951..6fe325b 100644
--- a/b2/lang.l
+++ b/b2/lang.l
@@ -25,6 +25,8 @@
 
 extern int yyparse(void);
 
+const char *file_name_override;
+
 static int start_token;
 static int expose_nl;	/* 0: ignore \n; 1: return TOK_NL */
 static int pattern;	/* 0: = relops are normal; 1: relops switch to PAT */
@@ -56,7 +58,8 @@ static void do_parse(const char *name, int start, int nl, int pat)
 	start_token = start;
 	expose_nl = nl;
 	pattern = pat;
-	file_name = unique(name);
+	file_name = file_name_override ? file_name_override : unique(name);
+	file_name_override = NULL;
 	lineno = 1;
 	yyparse();
 }