Assume that you have a number of files, downloaded from the internet, in the /home/kumar/download directory. The table of contents (TOC) is available in the file TOC_Download.txt in the form filename:description. The script should check each file in the download directory that does not have a description in the TOC file and prompt the user for the description. The TOC should be updated to maintain the list in sorted condition. The script must be immune to signals.