There is a problem with bash completion with quote_readline that causes the completion to fail. The problem is fixed in the bash completion package but there are still some other programs which are using the problematic code. Here is a way to find and resolve it.
First find the problematic program, most likely the recent one after which you started having the problems. Once that is found, find the file containing the definition of the function \”_filedirs()\”. Now, delete this file and create a symbolic link to the bash_completion file in the /etc directory. If this file is not present then you need to install the bashcompletion package.