update readme

README.md

@@ -1,6 +1,26 @@
 # befehl
-Run arbitrary commands over ssh in mass
+## Run arbitrary commands over ssh in mass
 
-- run payload.sh in PWD on IPs in targets.txt in PWD.. up to 100 at a time.
+- run payload.sh in PWD on IPs in targets in PWD.. up to 2000 at a time.
 
-`./befehl -targets targets.txt -payload payload.sh -routines 100`
+`./befehl execute --hosts targets --payload payload.sh -routines 2000`
+
+Output of each payload run will be in the log directory (by defualt, its `$HOME/befehl/logs`) in a file named after the machine it ran on.
+
+## Configuration
+
+You can configure befehl with a config file (~/.befehl.[toml|json|yaml]) any serialization format that upstream viper supports befehl supports for the config file. Valid configuration options:
+
+```toml
+[general]
+logdir = "/home/ssullivan/log-special"
+[auth]
+privatekeyfile = "/home/ssullivan/alt/.ssh/id_rsa"
+sshuser = "nonrootuser"
+```
+
+These options should be self explanatory so I wont describe what each does here.
+
+## Building
+
+Once you have your Go environment setup, it should be as simple as cloning this git repo and running `make`. The resulting binary will be located at `_exe/befehl`.