I didn't remember ever since when my Bash filename and directory name completion functioned wackily. Everytime I hit 'tab' to complete a directory name, Bash didn't append the backslash nor printed out candidates (just like what it described like here and here). It drove me banana. Meanwhile, my Bash worked very well under other Linux distributions (openSUSE, CentOS). The culprit was the a Bash completion file for adobe acrobat reader under /etc/bash_completion.d/. Delete it and the problem will be solved.