How do I keep terminal line from overwriting itself? [duplicate]

In a terminal window any smaller than fullscreen, if I type in a long command it starts overwriting the current line I'm on. If I type an additional line's worth, it finally moves to the next line. Does anyone know how to fix this?

This is what happens visually:

Edit: These are my prompt settings:

PS1='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\u@\h:\w\033[1m`__git_ps1`\033[0m\$ '
TERM=xterm

.bashrc:

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\033[1m`__git_ps1`\033[0m\$ '
fi

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

For some reason the terminal size is mis-reporting. It should change when you resize the terminal.

Try this in your .bashrc command file:

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

I found the answer here. The answer with the most votes solved it for me.

To sum it up I had to wrap my formats in \[ \]
export PS1='\[\033[1;32m\]$(whoami)@$(hostname): \[\033[0;37m\]$(pwd)$ \[\033[0m\]'