Update 'README.md'

README.md

@@ -30,6 +30,10 @@ This creates `threads.html` and extracts all information into the directory.
 
 ## File Management
 
+### List number of files (for instance, # of .mp4)
+
+```ls *.mp4 | cat -n```
+
 ### Recursively Zip subdirectories into their own .zip files
 
 ```for i in */; do zip -r "${i%/}.zip" "$i"; done```