Update cowsay.md

Print for the different options

pages/common/cowsay.md

@@ -1,6 +1,8 @@
 # cowsay
 
 > Generate an ASCII character like a cow or sheep saying or thinking something.
+> Available characters are stored in the /usr/share/cowsay on Linux.
+> and /usr/local/share/cows/ on Mac. directory.
 
 - Print an ASCII cow saying "Hello world!":
 
@@ -13,3 +15,8 @@
 - Print a stoned thinking ASCII cow:
 
 `cowthink -s "I'm just a cow, not a great thinker ..."`
+
+- Print out a list of all characters with cowsay: 
+
+`ls -1 {{cowsay_character_directory}}  | rev | cut -c 5- | rev | xargs -I _ cowsay -f _ cowsay -f _`
+