cheat sheets.

keyboard shortcuts: 

Moving around

Ctrl-a  Move the cursor   ⇤ to the start of the line
Ctrl-e  Move the cursor   ⇥ to the end of the line

Alt-b Move the cursor one word  ⇦ to the left
Alt-f Move the cursor one word  ⇨ to the right
Ctrl-x-x Move the cursor    ⇤⇥ to the start, and to the end again

Cut, copy and paste

Ctrl-u  Delete everything  ⇤ from the cursor back to the line start
Ctrl-k  Delete  everything  ⇥ from the cursor to the end of the line
Alt-d   Delete  word  ⇨ untill before the next word boundary
Ctrl-w  Delete  word  ⇦ untill after the previous word boundary
Ctrl-y Yank/Paste  prev. killed text at the cursor position

Undo

Ctrl-_ 
Ctrl+-  Undo the last editing command; you can undo all the way back to an empty
line

History

Ctrl-p  Move in history one line  ⇧ before this line
Ctrl-n  Move in history one line  ⇩ after this line
Alt-> Move in history all the lines ⇩ to the line currently being entered
Ctrl-r  Incrementally search the line history ⇧ backwardly
Ctrl-s  Incrementally search the line history ⇩ forwardly
Ctrl-J  End an incremental search
Ctrl-G  Abort an incremental search and restore the original line



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Integrate readline into a ruby program:

require 'readline'

while line = Readline.readline('> ', history = true)
  break if line =~ /^(quit|exit)$/
  puts "You typed: #{line.inspect}"
end
puts "Bye!"

# completion

require 'abbrev'

Completors = %w[hello world of nifty_completion]

Readline.completion_proc = lambda{|tok| Completors.abbrev[tok] }