Question: Use case is:

I type a long command and then I realize I need to run something else first.

I usually run it then CTRL C immediately.

I guess I could also do `echo "command" >> $HISTFILE`, but that won't work with quotes.

Answer: 
Just use `history -s arg`.

> 
> -s The args are added to the end of the history list as a single entry. 
> 
> 
> 

<http://ss64.com/bash/history.html>
Another alternative is to put a hash at the front of the line:

```
# echo this command will not execute, but it will be in the history.

```