What the author says about aliases in the bashrc being evaluated only once when the bashrc is run when the shell session is opened is wrong.

Go ahead and try this:

Put,

    alias lb='vim ~/logbook/$(date "+%s")'

in your bashrc.

Source the bashrc.

Run the lb command. It creates a new file with a different epoch timestamp each time. This `lb` command doesn't need to be a bash function. It can be an alias and work just fine.

Maybe how this works in zsh is different...