how do I learn what -i and -r and all those things do?
Those are command line arguments. Most programs come with a --help option that list out every possible one you can use and what they all do.
For example, if I typed "xrandr --help" into the terminal:
usage: xrandr [options]
where options are:
-display <display> or -d <display>
-help
-o <normal,inverted,left,right,0,1,2,3>
or --orientation <normal,inverted,left,right,0,1,2,3>
-q or --query
-s <size>/<width>x<height> or --size <size>/<width>x<height>
-r <rate> or --rate <rate> or --refresh <rate>
-v or --version
-x (reflect in x)
-y (reflect in y)
--screen <screen>
--verbose
--current
--dryrun
--nograb
--prop or --properties
--fb <width>x<height>
--fbmm <width>x<height>
--dpi <dpi>/<output>
--output <output>
--auto
--mode <mode>
--preferred
--pos <x>x<y>
--rate <rate> or --refresh <rate>
--reflect normal,x,y,xy
--rotate normal,inverted,left,right
--left-of <output>
--right-of <output>
--above <output>
--below <output>
--same-as <output>
--set <property> <value>
--scale <x>x<y>
--transform <a>,<b>,<c>,<d>,<e>,<f>,<g>,<h>,<i>
--off
--crtc <crtc>
--panning <w>x<h>[+<x>+<y>[/<track:w>x<h>+<x>+<y>[/<border:l>/<t>/<r>/<b>]]]
--gamma <r>:<g>:<b>
--primary
--noprimary
--newmode <name> <clock MHz>
<hdisp> <hsync-start> <hsync-end> <htotal>
<vdisp> <vsync-start> <vsync-end> <vtotal>
[+HSync] [-HSync] [+VSync] [-VSync]
--rmmode <name>
--addmode <output> <name>
--delmode <output> <name>
It's basically the program used to set your resolutions and stuffs. You can do
tons with it though; even with my complicated setup I only use 10% of these arguments.