function popd
{
    mypath="/home/app2/dep_sjq/tmp/tmpfj"
    current_pid=$$
    parent_id=$(ps -o pid,ppid,comm | grep $current_pid | awk -v current_pid_var=$current_pid '$1==current_pid_var{print $2}')
    file="$mypath/${parent_id}.dir"
    if [ -f "$file" ]
    then
        path=`head -n 1 $file`
        if [ -z "$path"  ]; then
            echo 'empty stack'
            return;
        else
            cd $path
            content=`sed '1d' "$file"`
            echo "$content" > $file
            return;
        fi
    else
        echo 'no file'
    fi
}

function pushd
{
    mypath="/home/app2/dep_sjq/tmp/tmpfj"
    current_pid=$$
    if [ ! -d "${mypath}" ]
    then
        mkdir "${mypath}"
    fi
    parent_id=$(ps -o pid,ppid,comm | grep $current_pid | awk -v current_pid_var=$current_pid '$1==current_pid_var{print $2}')
    file="$mypath/${parent_id}.dir"
    if [ ! -f "$file" ]
    then
        touch $file
    fi
    filecontent=`cat $file`
    pwd > $file
    echo "$filecontent" >> $file
   # sed  "1 i ${PWD}" "$file" > $file
    oldpath=$PWD
    cd $1
    echo "$oldpath  -->  $PWD"
}