Added /version command that outputs commit the server was built on.

Makefile

@@ -8,7 +8,7 @@ all: $(BINARY)
 	go build ./...
 
 $(BINARY): **/*.go *.go
-	go build .
+	go build -ldflags "-X main.buildCommit `git rev-parse --short HEAD`" .
 
 deps:
 	go get .

client.go

@@ -431,6 +431,8 @@ func (c *Client) handleShell(channel ssh.Channel) {
 						}
 					}()
 				}
+			case "/version":
+				c.SysMsg("Version " + buildCommit)
 
 			default:
 				c.SysMsg("Invalid command: %s", line)

cmd.go

@@ -33,6 +33,7 @@ var logLevels = []log.Level{
 	log.Debug,
 }
 
+var buildCommit string
 func main() {
 	options := Options{}
 	parser := flags.NewParser(&options, flags.Default)