How do you search a binary file for a certain string that ends in a number; but you are not sure what the number is? Then this command will perform this task.
john@adeptus-mechanicus ~/Documents/master $ strings vesperas.wad | grep -a "MAP[0-9]" MAP15
I was using this command as I had a folder full of Doom wadfiles and I could use this to see what level number they were to play them. This shows how flexible and useful the BASH shell is.
Here is another example with ls.
john@adeptus-mechanicus ~/Documents $ ls -hula time[0-9].c -rw-r--r-- 1 john john 802 Oct 7 2011 time3.c
This example below shows that you can couple wildcards with this technique to display a listing of the files that you are after.
john@adeptus-mechanicus /mnt/Elements/Wallpapers $ ls -hula space-[0-9]* -rwxrwxrwx 1 root root 74K Nov 26 2011 space-01.jpg -rwxrwxrwx 1 root root 82K Dec 29 2011 space-02.jpg -rwxrwxrwx 1 root root 31K Dec 29 2011 space-03.jpg -rwxrwxrwx 1 root root 77K Dec 29 2011 space-04.jpg -rwxrwxrwx 1 root root 15K Dec 29 2011 space-05.jpg
As you can see, this is one useful technique that could come in handy when you are searching a folder with a heap of files for one or two that match certain criteria. Very useful indeed.