Add List Of Sessions To A Machine as a unix til

README.md

@@ -7,7 +7,7 @@ variety of languages and technologies. These are things that don't really
 warrant a full blog post. These are mostly things I learn by pairing with
 smart people at [Hashrocket](http://hashrocket.com/).
 
-_445 TILs and counting..._
+_446 TILs and counting..._
 
 ---
 
@@ -401,6 +401,7 @@ _445 TILs and counting..._
 - [Last Argument Of The Last Command](unix/last-argument-of-the-last-command.md)
 - [Less With Style](unix/less-with-style.md)
 - [List All Users](unix/list-all-users.md)
+- [List Of Sessions To A Machine](unix/list-of-sessions-to-a-machine.md)
 - [Only Show The Matches](unix/only-show-the-matches.md)
 - [Open The Current Command In An Editor](unix/open-the-current-command-in-an-editor.md)
 - [Partial String Matching In Bash Scripts](unix/partial-string-matching-in-bash-scripts.md)

unix/list-of-sessions-to-a-machine.md

@@ -0,0 +1,16 @@
+# List Of Sessions To A Machine
+
+The `last` command is a handy way to find out who has been connecting to a
+machine and when.
+
+> Last will list the sessions of specified users, ttys, and hosts, in
+> reverse time order.  Each line of output contains the user name, the tty
+> from which the session was conducted, any hostname, the start and stop
+> times for the session, and the duration of the session.  If the session is
+> still continuing or was cut short by a crash or shutdown, last will so
+> indicate.
+
+In particular, this can be useful for finding an IP address that you want to
+connect to.
+
+See `man last` for more details.