Nook: update busybox version & use Putty to connect to Nook (ADB)

Disclaimer: this post is addressed to advanced users, that have experience with Linux command line interface, and that are confortable connecting to Nook using ADB (or telnet/ssh).

The busybox version included in Nook is quite old. Updating it to a new one could be useful, for  having access to both new commands and features.

The procedure to update busybox is really simple:

1. download and unizp busybox (or directly from busybox site);
2. (optional) to be on safe side, make a backup of current busybox binary, placed into /system/bin;
3. using adb, copy new busybox executable to nook, folder /system/bin, renaming it busybox;
4. change owner and permissions of new busybox file:
   chmod 744 /system/bin/busybox
   chown system.system /system/bin/busybox

In my case (maybe using other configuration this could be different), using the updated busybox results in a easier usage of ADB enhanced Putty client to connect to Nook: infact, both autocomplete by tab key and command history (up key) work correctly.

Tip: if you add in file /init.rc the following row (about at the start of the file, where also others env variables are set):

export ENV /ash_startup_script ash

you can then create the file /ash_startup_script. In this file you can add whatever you want, that will be executed at session shell creation. In my case, for instance, i put the alias for ll, so that i don't have to define it manually each time i start a shell session:
alias ll=ls -l"