Cisco IOS "help" and "show" options available at the USER MODE prompt:

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


Router>help

Help may be requested at any point in a command by entering
a question mark '?'.  If nothing matches, the help list will
be empty and you must backup until entering a '?' shows the
available options.
Two styles of help are provided:
1. Full help is available when you are ready to enter a
   command argument (e.g. 'show ?') and describes each possible
   argument.
2. Partial help is provided when an abbreviated argument is 
   entered and you want to know what arguments match the input
   (e.g. 'show pr?'.)




Router>show version

Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-I-M), Version 12.2(12k), 
    RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2004 by cisco Systems, Inc.
Compiled Thu 18-Nov-04 14:36 by kellmill
Image text-base: 0x8000808C, data-base: 0x809E3688

ROM: System Bootstrap, Version 12.2(8r) [cmong 8r], 
     RELEASE SOFTWARE (fc1)

Router uptime is 1 hour, 49 minutes
System returned to ROM by power-on
System image file is "flash:c2600-i-mz.122-12k.bin"

cisco 2620XM (MPC860P) processor (revision 0x400) 
  with 125952K/5120K bytes of memory.
Processor board ID JMX0850L39T (2542284945)
M860 processor: part number 5, mask 2
Bridging software.
X.25 software, Version 3.0.0.
Primary Rate ISDN software, Version 1.1.
Basic Rate ISDN software, Version 1.1.
1 FastEthernet/IEEE 802.3 interface(s)
2 Low-speed serial(sync/async) network interface(s)
1 ISDN Basic Rate interface(s)
1 Channelized T1/PRI port(s)
32K bytes of non-volatile configuration memory.
32768K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102





Router>show flash:

System flash directory:
File  Length   Name/status
  1   5429868  c2600-i-mz.122-12k.bin
[5429932 bytes used, 27600212 available, 33030144 total]
32768K bytes of processor board System flash (Read/Write)