Enable alt/ctrl + left/right on CentOS command line

Thanks to your question I finally did some reading and increased my understanding, cheers!

So, a very good source of information is man readline. The keybindings specified in the various inputrc files control the way that the BASH readline library works. According to the readline manpage you can use either symbolic key names or escape sequences:

   Key Bindings
       The syntax for controlling key bindings in the inputrc file is
       simple.  All that is required is the name of  the  command  or
       the  text  of a macro and a key sequence to which it should be
       bound. The name may be specified in one of two ways: as a sym‐
       bolic  key  name, possibly with Meta- or Control- prefixes, or
       as a key sequence.  The name and key sequence are separated by
       a  colon.  There can be no whitespace between the name and the
       colon.

       When using the form keyname:function-name or macro, keyname is
       the name of a key spelled out in English.  For example:

              Control-u: universal-argument
              Meta-Rubout: backward-kill-word
              Control-o: "> output"

The man page also states that the default configuration file is ~/.inputrc so I recommend placing your bindings there.

If you want to use normal letter keys (for example Control-g), Control-g: forward-word works fine. The arrow keys are harder. I tried, and failed, to find the key name for the arrow keys. None of the ones I tried (left-arrow, left, :left) worked so it seems like we are stuck with the escape sequences.

Unfortunately, the exact escape sequence differs between terminal emulators (that is why your Ubuntu inputrc had multiple lines). To find out which escape sequence your favorite terminal uses, run read and then type the key sequence you are interested in. In terminator, xterm and gnome-terminal, Control-Left give:

$ read
^[[1;5D

in aterm:

$ read
^[Od    <-- that is a capital O not a zero (0).

By experimenting a bit, I figured out that ^[[D is Left and ^[[1;5D is Control-Left. The first ^[ is the Esc key, used here, I suppose, to denote an escape sequence.

In any case, to bind Control-Left to forward-word in a way that works for all, I added these lines to my ~/inputrc:

"\e[1;5D": backward-word
"\eOd": backward-word

For reasons I have not fully understood, Control is represented by \e which should be Esc.

My final ~/.inputrc file that works for all the terminals listed above is:

"\e[1;5D": backward-word
"\eOd": backward-word
"\e[1;5C": forward-word
"\eOc": forward-word