Add Count the Number of Matches as a vim til.

vim/count-the-number-of-matches.md

@@ -0,0 +1,31 @@
+# Count the Number of Matches
+
+You can use the substitution functionality in vim to count the number
+of matches for a given search term like so:
+
+```
+:%s/transaction_id//n
+```
+
+You will see the result in the command tray like so:
+
+```
+8 matches on 8 lines
+```
+
+If you want to find matches globally (that is, counting multiples per line),
+you can add the `g` flag:
+
+```
+:%s/transaction_id//gn
+```
+
+for a response like:
+
+```
+13 matches on 8 lines
+```
+
+The magic is in the `n` flag which tells vim to report a count of the
+matches and not actually perform the substitution. See `:h :s_flags` for
+more details. Also, check out `:h count-items`.