Setting PS1 with color codes properly with gnome-terminal

There are plenty of web pages describing the different escape codes for changing color of an ANSI emulating terminal. This is in particular useful for giving the shell prompt different colors, to prevent confusion between different computers, for example.

The trick is to set the PS1 bash variable. What is less told, is that \[ and \] tokens must enclose the color escape sequence, or things get completely crazy: Pasting into the terminal creates junk, newlines aren’t interpreted properly and a lot of other peculiarities with the cursor jumping to the wrong place all the time.

So this is wrong (just the color escape sequence, no enclosure):

PS1="\e[44m[\u@here \W]\e[m\\$ "

And this is right:

PS1="\[\e[44m\][\u@here \W]\[\e[m\]\\$ "

Even the “wrong” version about will produce the correct colors, but as mentioned above, other weird stuff happens.