Open Preference Pane from command line on El Capitan (Mac OS X 10.11)
You can open System Preferences using its URL scheme:

open "x-apple.systempreferences:"


You can jump to a specific anchor on a specific pane using:

open "x-apple.systempreferences:com.apple.preference.keyboard?Text"


You can get the list of panes and anchors using AppleScript:

tell application "System Preferences"
    set myIds to the id of every pane
    set myAnchors to anchors of current pane
end tell 


Update: Apple has restricted use of the URL scheme in 10.11. As of this release only preference panes with NSPrefPaneAllowsXAppleSystemPreferencesURLScheme set in their Info.plist can be opened via the URL scheme.

Source: @Matt Stevens answer