added the start of a user guide

docs/index.md

@@ -21,7 +21,7 @@ PsychOS is a multi-user cooperative multitasking operating system for OpenComput
 ### Documentation
 
 - [Installation guide](install.html)
-- User guide (WIP)
+- [User guide](userguide.html) 
 - [Building PsychOS](building.html)
 - [API documentation](api.html)
 - [Filesystem layout](fhs.html)

docs/userguide.md

@@ -0,0 +1,67 @@
+# PsychOS user guide
+
+## Useful key combinations:
+`ctrl-shift-c` inside PsychOS will cancel text input or stop certain programs.
+
+`ctrl-shift-r` will soft-reboot the machine, preserving the content of `/tmp`.
+
+## The lush shell
+lush is the default shell of PsychOS. It allows executing functions in memory, programs on disk and Lua typed directly into lush, in order of preference.
+
+The default prompt is `[<user>@<hostname> <current directory>]$`
+
+Some example usage:
+
+### running a function
+```
+[user@host /boot]$ =ps  
+function: 0x12ed5c0
+```
+
+This is checking if ps is indeed a function.
+
+```
+[user@host /boot]$ ps  
+PID     User    Name  
+3       superu  logflushd  
+4       superu  ncd  
+5       superu  tty[randomstringabcd]: 8f01b7c7,89734f0  
+6       superu  kbd: 1f46ed58  
+7       superu  kbd-clibboard: 1f46ed58  
+8       superu  login manager: randomstringabcd
+```
+
+This runs the ps function. You can also have arguments following the function name, separated by spaces.
+
+### running a program on disk
+
+You have the following program stored as count.lua, in the current directory:
+
+```
+for i = 1, 5 do  
+ print(i)  
+end
+```
+
+To run it, all you need to do is:  
+```
+[user@host /boot]$ count
+```
+
+You should get the expected output:  
+```
+1  
+2  
+3  
+4  
+5
+```
+
+### running Lua code
+Running Lua from lush is also simple, in that you just type it in.
+
+```
+[user@host /boot]$ for i = 1, 5 do print(i) end
+```
+
+You should get the same output as the last example.