Hi.
There might be an easier way to do this. But this works for me.
This is to display the 8th line of my /etc/passwd file for example
cat -n /etc/passwd | grep 8
In your case you could do cat -n /your/file.txt | grep 56
Again, there is probably an easier way to do it, but I've always used this because I've never found another way
cat -n that will output and number each line, grep grabs what ever you enter after it. So it is basically numbering the output lines (not changing the file at all) and then showing the whole line you need.
Obviously just ignore the number it outputs for you.
>Craig