OK, that's a long one. Let's see...
I'm not quite sure, how you entered that command, but I'll tell you about the parts of it that I understand.
- Most things behind an exclamation mark is treated as external commands from within vi. So I assume, that the part date +%A|wc -m is meant to operate in that way. This command actually uses two programs: date (which gives information about the current date) and wc (which counts various things).
- Here, we have date +%A which, according to man date gives you the name of the day of the week (e.g. Wednesday today).
- That name is piped to the command wc -m with that | operator.
- wc -m counts the number of characters in whatever it is given. (Check man wc for more information.) So, date +%A | wc -m will give you the number of characters in the current day of the week.
- The :r command will read an external file. So, if you enter [i]:r!date|wc -m while running vi, it will enter the amount of characters in the current date into the file you're just editing. However, vi complains about the % with me. You can escape it with the following command:
If you tell us, how exactly you entered this command (where you within vim maybe? Or did you try to use
vi 14...?), I'm sure we can help you some more.
Greetings,
Nepomuk