.bashrc break, second line entered in shell eats up first line

I've using a .bashrc from one of peepcode's screencast.

# If not running interactively, don't do anything
[ -z "$PS1" ] && return

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

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "$debian_chroot" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, overwrite the one in /etc/profile)
PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '

# Commented out, don't overwrite xterm -T "title" -n "icontitle" by default.
# If this is an xterm set the title to user@host:dir
#case "$TERM" in
#xterm*|rxvt*)
#    PROMPT_COMMAND='echo -ne "\033]0;${USER}@${HOSTNAME}: ${PWD}\007"'
#    ;;
#*)
#    ;;
#esac

# enable bash completion in interactive shells
#if [ -f /etc/bash_completion ] && ! shopt -oq posix; then
#    . /etc/bash_completion
#fi

# sudo hint
if [ ! -e "$HOME/.sudo_as_admin_successful" ]; then
    case " $(groups) " in *\ admin\ *)
    if [ -x /usr/bin/sudo ]; then
    cat <<-EOF
    To run a command as administrator (user "root"), use "sudo <command>".
    See "man sudo_root" for details.

    EOF
    fi
    esac
fi

# if the command-not-found package is installed, use it
if [ -x /usr/lib/command-not-found -o -x /usr/share/command-not-found ]; then
    function command_not_found_handle {
            # check because c-n-f could've been removed in the meantime
                if [ -x /usr/lib/command-not-found ]; then
           /usr/bin/python /usr/lib/command-not-found -- $1
                   return $?
                elif [ -x /usr/share/command-not-found ]; then
           /usr/bin/python /usr/share/command-not-found -- $1
                   return $?
        else
           return 127
        fi
    }
fi

. ~/bin/bash_colors.sh

#load bash aliases
if [ -f ~/.bash_aliases ]; then
. ~/.bash_aliases
fi

# Unbreak broken, non-colored terminal
export TERM='xterm-color'
alias ls='ls -G'
alias ll='ls -lG'
export LSCOLORS="ExGxBxDxCxEgEdxbxgxcxd"
export GREP_OPTIONS="--color"

# Erase duplicates in history
export HISTCONTROL=erasedups
# Store 10k history entries
export HISTSIZE=10000
# Append to the history file when exiting instead of overwriting it
shopt -s histappend

function minutes_since_last_commit {
    now=`date +%s`
    last_commit=`git log --pretty=format:'%at' -1`
    seconds_si开发者_运维技巧nce_last_commit=$((now-last_commit))
    minutes_since_last_commit=$((seconds_since_last_commit/60))
    echo $minutes_since_last_commit
}
grb_git_prompt() {
    local g="$(__gitdir)"
    if [ -n "$g" ]; then
        local MINUTES_SINCE_LAST_COMMIT=`minutes_since_last_commit`
        if [ "$MINUTES_SINCE_LAST_COMMIT" -gt 30 ]; then
            local COLOR=${RED}
        elif [ "$MINUTES_SINCE_LAST_COMMIT" -gt 10 ]; then
            local COLOR=${YELLOW}
        else
            local COLOR=${GREEN}
        fi
        local SINCE_LAST_COMMIT="${COLOR}$(minutes_since_last_commit)m${NORMAL}"
        # The __git_ps1 function inserts the current git branch where %s is
        local GIT_PROMPT=`__git_ps1 "(%s|${SINCE_LAST_COMMIT})"`
        echo ${GIT_PROMPT}
    fi
}

export PS1='$(grb_git_prompt)$ '

gd() { git diff $* | view -; }
gdc() { gd --cached $*; }

source ~/bin/git-completion.bash

I can confirm the error is in grb_git_promit. What happens is the second lines typed in shell is overwriting the first line. Can anyone could help me with this?

EDIT:

grb_git_prompt() {
    local g="$(__gitdir)"
    if [ -n "$g" ]; then
        local MINUTES_SINCE_LAST_COMMIT=`minutes_since_last_commit`
        if [ "$MINUTES_SINCE_LAST_COMMIT" -gt 30 ]; then
            local COLOR="\[\033[0;31m\]"
        elif [ "$MINUTES_SINCE_LAST_COMMIT" -gt 10 ]; then
            local COLOR="\[\033[0;37m\]"
        else
            local COLOR="\[\033[0;32m\]"
        fi
        local SINCE_LAST_COMMIT="${COLOR}$(minutes_since_last_commit)m$"
        # The __git_ps1 function inserts the current git branch where %s is
    echo "$(__git_ps1 '(%s|')${SINCE_LAST_COMMIT}"
    fi
}

When you have colors and other non-printing escape sequences in your prompt, you have to surround them with escaped single brackets. Here is a simple example:

PS1='\[\033[38;5;1m\]some red text\[\033[0m\]\$ '

Which will cause the prompt to display "some red text" in red and the dollar sign (or "#") in the default color.

Here is another way to do the same thing:

red='\033[38;5;1m'
none='\033[0m'
PS1='\[$red\]some red text\[$none\]\$ '

By the way, to do this more portably and have less complex build-up of variables:

red=$(tput setaf 1)
none=$(tput sgr0)

See man 5 terminfo for more information on the settings.