diff -r 4679f67a8324 -r 7471529c0d11 src/FilesystemCommand.h
--- a/src/FilesystemCommand.h	Fri Jan 24 16:53:31 2020 +0100
+++ b/src/FilesystemCommand.h	Fri Jan 24 21:05:10 2020 +0100
@@ -75,7 +75,7 @@
 		return configuration->relation.empty() ? L"filesystem" : configuration->relation;
 	}
 
-	void writeHeader(RelationalWriter* writer, std::map<string_t, std::shared_ptr < AttributeFinder>> attributeFinders, string_t relationName, std::vector<RequestedField>* fields) {
+	void writeHeader(RelationalWriter* writer, std::map<string_t, std::shared_ptr < AttributeFinder>> attributeFinders, string_t relationName, std::vector<RequestedField>* fields, bool writeHeader = true) {
 		std::vector<AttributeMetadata> attributesMetadata;
 		for (RequestedField field : *fields) {
 			std::shared_ptr<AttributeFinder> finder = attributeFinders[field.group];
@@ -83,7 +83,27 @@
 			else throw RelpipeWriterException(L"Unsupported field group: " + field.group);
 		}
 
-		writer->startRelation(relationName, attributesMetadata, true);
+		writer->startRelation(relationName, attributesMetadata, writeHeader);
+	}
+
+	void processSingleFile(std::shared_ptr<RelationalWriter> writer, std::stringstream& originalName, std::map<string_t, std::shared_ptr < AttributeFinder>>&attributeFinders, Configuration& configuration, string_t relationName) {
+		fs::path file(originalName.str().empty() ? "." : originalName.str()); // interpret empty string as current directory (e.g. result of: find -printf '%P\0')
+		bool exists = false;
+
+		try {
+			exists = fs::exists(file);
+		} catch (const fs::filesystem_error& e) {
+			// we probably do not have permissions to given directory → pretend that the file does not exist
+		}
+
+		for (auto& finder : attributeFinders) finder.second->startFile(file, originalName.str(), exists);
+
+		for (RequestedField field : configuration.fields) {
+			std::shared_ptr<AttributeFinder> finder = attributeFinders[field.group]; // should not be nullptr, because already checked while writing the relation metadata
+			finder->writeField(writer.get(), relationName, field);
+		}
+
+		for (auto& finder : attributeFinders) finder.second->endFile();
 	}
 
 public: