It's hard to find information on this, and I've often wondered it myself, but it seems to stand for "all". Even the Nethack Wiki doesn't define "ynaq".

In the case of item accumulation:

• Typing “y” picks up that item, and displays the next.
• Typing “n” displays the next item.
• Typing “a” picks up that item, and all remaining items of the named types. The program will not allow the player to pick up any item which is too heavy.
• Typing “q” aborts the command.

In the case of starting a new game, it would make all relevant choices for you so the game can begin in earnest.

Do note that when pressing "q" your character will be deleted. It's best to save instead using Shift + S.

References:

https://thekill08.wordpress.com/2008/03/15/hack-and-nethack-the-software-distillery/ ftp://ftp.cuhk.edu.hk/pub/oldies/apple2/unsorted/Hack.txt

It's hard to find information on this, and I've often wondered it myself, but it seems to stand for "all". Even the Nethack Wiki doesn't define "ynaq".

In the case of item accumulation:

• Typing y picks up that item, and displays the next.
• Typing n displays the next item.
• Typing a picks up that item, and all remaining items of the named types. The program will not allow the player to pick up any item which is too heavy.
• Typing q aborts the command.

In the case of starting a new game, it would make all relevant choices for you so the game can begin in earnest.

Do note that when pressing q your character will be deleted. It's best to save instead using Shift+S.

References:

https://thekill08.wordpress.com/2008/03/15/hack-and-nethack-the-software-distillery/ ftp://ftp.cuhk.edu.hk/pub/oldies/apple2/unsorted/Hack.txt