added something to read

README.md

 # sanipy
 
+sanipy is a command-line tool for epics connection testing.
+
+It has two commands ([check](check) and [compare](compare)) and a few option switches (check `sani.py -h` and `sani.py COMMAND -h`).
+
+The `data` folder contains some channel lists and output files for testing.
+
+## check
+
+`./sani.py check data/test_chans_good.txt`
+<img src="docs/check_good.png" width="491">
+
+`./sani.py check data/test_chans_bad.txt`
+<img src="docs/check_bad.png" width="491">
+
+
+## compare
+
+`./sani.py compare data/test1.csv data/test4 -v`
+<img src="docs/compare_good.png" width="568">
+
+`./sani.py compare data/test1.csv data/test3`
+<img src="docs/compare_bad.png" width="658">
+
+(Note here that `.csv` is automatically appended if missing.)