README: describe how the flow of scan command

1 files changed, 26 insertions, 0 deletions

diff --git a/README.md b/README.md
index b000448..e4f51d3 100644
--- a/README.md
+++ b/README.md
@@ -247,6 +247,32 @@ changes the behaviour of apply command.
 Deleting a line in the report means excluding the file from being processed
 by "apply" command.
 
+The scan command work in the following way,
+
+(1) Check the file for SPDX-License-Identifier and SPDX-FileCopyrightText.
+If both exist, skip the file.
+
+(2) For each match-license in the configuration,
+
+(2.1) If there is a match, record it as "match" and its line number
+into the report.
+
+(2.2) If no match, use the default license from configuration, record it as
+"default" with 0 line number in the report.
+
+(3) For each match-copyright in the configuration,
+
+(3.1) If there is a match, get the year, author, and contact; and record it
+as "match" and its line number into the report.
+
+If the year is empty, try to get the year from the first commit of the file
+using "git log --follow ..." command.
+If no commit history or its not using git, use default copyright year from
+configuration.
+
+(3.2) If there is no match, use default copyright year and text from
+configuration, and record as "default" in the report.
+
 ### spdxconv.report file format
 
 Each line in the report file is formatted using CSV and has several columns