bashrc if：表达式语法错误

# .bashrc
# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi

# User specific aliases and functions


function up( )
{
LIMIT=$1
P=$PWD
for ((i=1; i <= LIMIT; i++))
do
    P=$P/..
done
cd $P
export MPWD=$P
}

function back( )
{
LIMIT=$1
P=$MPWD
for ((i=1; i <= LIMIT; i++))
do
    P=${P%/..}
done
cd $P
export MPWD=$P
}

但是,保存后,当我执行源.bashrc时,我收到以下错误：if：Expression Syntax.

我究竟做错了什么 ？我用谷歌搜索了一段时间但没有用.