added printf.md and tested it

_commands/basics/printf.md

@@ -0,0 +1,71 @@
+---
+---
+
+printf
+-------
+
+print formatted ouput.
+works like the c function of the same name.
+
+~~~ bash
+printf FORMAT ARGS
+
+example:
+printf "My name is \"%s\".\n The args can be nums %i." "Ryan" 2
+
+output:
+"My name is Ryan.
+The args can be nums 2."
+~~~
+
+<!--more-->
+
+### Useful Options / Examples
+
+Like most commands printf also has a --help option
+Some other interesting things to note:
+
+#### variable types
+
+%i = integer
+
+%d = decimal
+
+%o = octal
+
+%x = hex
+
+%u = unsigned int
+
+%c = character
+
+%s = string
+
+%f = float
+
+%e = scientific float (engineering)
+
+%p = pointer
+
+%% = percent sign
+
+#### modifiers
+
+You can modify the variables in different ways:
+number = amount of space to occupy
+\- = pad to the left
+.number = max amount of characters to use
+
+##### Examples
+
+"%8s" "hi"
+
+"      hi"
+
+"%-8s" "hi"
+
+"hi      "
+
+"%.4s" "hello everyone"
+
+"hell"