One years ago, this article was popular in hatebu. That time I could not understand questions quite. But I came to understand a little. I will write answer things about it as possible as. Under this text is a possibility that it is not true. May be I have made mistake.
q: Have you ever used to grep/tar/find command?
a: Yes. grep is regular expression to find file or line of file. If you input "*.txt", it returns file list. Tar is command which has compression and decompression. It is used to compress file or decompress, example follow to decompression is tar zxvf "*.tar". and decompress is tar cvf archive.tar /directory.