I always hate it when Cisco IOS asks me for things I've already supplied in a command line, the most notable case being the copy command. For example, if you supply the complete source and destination file name in the command line, IOS still insists on asking you all the same questions (at least filling in the parameters I've supplied in the command line):

fw#copy system:running-config tftp://10.0.0.2/fw-test
Source filename [running-config]?
Address or name of remote host [10.0.0.2]?
Destination filename [fw-test]?
!!
2009 bytes copied in 0.604 secs (3326 bytes/sec)

You can disable the annoying questions with the file prompt quiet configuration command (the default value of this parameter is noisy).

As part of Configuraton Change Notification and Logging feature, Cisco IOS stores the most recent configuration commands in a circular buffer and (optionally) sends them to syslog streams.

This feature is configured under the archive configuration mode with the log config command, which brings you to yet another configuration mode where you can fine-tune the parameters (they are obvious, on-router help is sufficient), for example:

The Cisco IOS’s AAA architecture contains many handy features, including authorizing and logging every CLI command executed on the router. Unfortunately, the AAA command accounting only supports TACACS+ as the AAA transport protocol, making it unusable in RADIUS environments.

You can use Embedded Event Manager as a workaround. The following configuration commands will log every command executed on the router.

Cisco IOS has the ability to define command aliases - short words that substitute a whole exec-mode or configuration command. These aliases can also be used in command execution URLs. For example, if you define alias exec showdefault show ip route 0.0.0.0 0.0.0.0, you can view the status of the default route with the http://router/exec/showdefault/CR URL.

Microsoft decided a while ago to disable the ability to send username and password encoded in URL to a web server. This "security patch" also prevents you from serving files from Cisco IOS web server without explicit user login (IOS web server does not support anonymous access). However, as the Microsoft patch does not affect FTP, you can use FTP server embedded in most Cisco IOS images and download files to your web browser with the ftp://user:password@router/file URL.

To enable FTP server in Cisco IOS, use the ftp-server enable configuration command followed by the ftp-server topdir directory command which specifies the top-level FTP directory (for example, flash:). To authenticate FTP users, define local usernames with the username user password password configuration command.

To optimize the space utilizations and file transfer operations in flash: memory, Cisco IOS web server allows files to be served from tar archives stored on flash: (or any other) filesystem. The URL syntax to access a file in a tar archive is /archive/archive-name-without-tar-suffix/file-in-archive.

Cisco IOS supports the Unix tar format with the archive command. For example, to inspect the contents of the Secure Device Manager (SDM) that is present in Flash memory on most routers, use the archive tar /table flash:sdm.tar command.

You can also use the archive tar /xtract command to extract a tar file (local or external) into a directory (yet again local or external). For example, with the command archive tar /xtract flash:sdm.tar tftp://10.0.0.10 you'd extract the SDM tar archive to a TFTP server.

Note: tar extract cannot create subdirectories on a TFTP server, the directory structure has to be prepared in advance.

Another un(der)documented fact: when you access the router's home page (assuming HTTP or HTTPS server has been enabled), the router displays:

1. The home.html file if it exists in any filesystem;
2. The home.shtml file if it exists in any filesystem;
3. a default page with links to exec, SDM, QDM and TAC support

Note: even though you can access home.html file on flash: device directly, that web page cannot reference any other file in flash: as a relative link unless you specify flash: as the default path for the HTTP requests with the ip http path flash: command.