Cisco IOS commands available at the PRIVILEDGED MODE prompt:

Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-I-M), Version 12.2(12k), 
    RELEASE SOFTWARE (fc1)

Router>enable

Router>en
Router#show ?
  access-expression    List access expression

  access-lists         List access control lists (ACL)

  accounting           Accounting data for active sessions
  adjacency            Adjacent nodes
  aliases              Display alias commands
  arp                  ARP table
  async                Information on terminal lines used 
                        as router interfaces
  backup               Backup status
  bridge               Bridge Forwarding/Filtering Database 
                        [verbose]
  buffers              Buffer pool statistics
  c2600                Show c2600 information
  cca                  CCA information
  cdapi                CDAPI information

  cdp                  Cisco Discovery Protocol information

  cef                  Cisco Express Forwarding
  class-map            Show QoS Class Map
  clock                Display the system clock
  compress             Show compression statistics

  configuration        Contents of Non-Volatile memory

  connection           Show Connection
  context              Show context information

  controllers          Interface controller status

  cops                 COPS information
  debugging            State of each debugging option
  derived-config       Derived operating configuration

  dhcp                 Dynamic Host Configuration Protocol 
                        status
  diag                 Show diagnostic information for port 
                        adapters/modules
  dialer               Dialer parameters and statistics
  dnsix                Shows Dnsix/DMDP information
  dxi                  atm-dxi information
  entry                Queued terminal entries
  environment          Environmental monitor statistics
  exception            exception informations
  file                 Show filesystem information

  flash:               display information about flash: 
                        file system

  frame-relay          Frame-Relay information

  history              Display the session command history

  hosts                IP domain-name, lookup style, 
                        nameservers, and host table

  html                 HTML helper commands
  idb                  List of Hardware Interface Descriptor 
                        Blocks
  
  interfaces           Interface status and configuration

  ip                   IP information

  isdn                 ISDN information
  key                  Key information
  line                 TTY line information
  llc2                 IBM LLC2 circuit information
  location             Display the system location
  logging              Show the contents of logging buffers
  memory               Memory statistics
  modemcap             Show Modem Capabilities database
  ntp                  Network time protocol
  parser               Display parser information
  pas                  Port Adaptor Information
  pci                  PCI Information
  policy-map           Show QoS Policy Map
  ppp                  PPP parameters and statistics
  printers             Show LPD printer information

  privilege            Show current privilege level

  processes            Active process statistics

  protocols            Active network routing protocols *

  qdm                  Show information about QoS Device 
                        Manager
  queue                Show queue contents
  queueing             Show queueing configuration
  radius               Shows radius information
  random-detect-group  display random-detetct group
  registry             Function registry information
  reload               Scheduled reload information
  rhosts               Remote-host+user equivalences
  rif                  RIF cache entries
  rmon                 rmon statistics
  route-map            route-map information
  rtr                  Response Time Reporter (RTR)

  running-config       Current operating configuration
                       (to see the sub-portion of the running-
                        config for a specific interface:
                        ex. sh run int s0                  )

  sessions             Information about Telnet connections
  smds                 SMDS information
  snapshot             Snapshot parameters and statistics
  snmp                 snmp statistics

  spanning-tree        Spanning tree topology

  stacks               Process stack utilization
  standby              Hot Standby Router Protocol (HSRP) 
                        information

  startup-config       Contents of startup configuration

  subscriber-policy    Subscriber policy
  subsys               Show subsystem information
  tacacs               Shows tacacs+ server statistics
  tcp                  Status of TCP connections
  tech-support         Show system information for Tech-Support
  template             Template information
  terminal             Display terminal configuration parameters
  tgrm                 Trunk Group Resource Mananger info
  time-range           Time range
  traffic-shape        traffic rate shaping configuration
  users                Display information about terminal lines

  version              System hardware and software status

  vtemplate            Virtual Template interface information
  whoami               Info on current tty line
  x25                  X.25 information
  x29                  X.29 information