Exec Command from Cisco Config Mode

IOS (Internetwork Operating System) has three mode management from telnet or console. That are unprivileged mode, privileged mode, config mode, in config mode there are more type config like interface config (int-conf), route config (route-config) etc. all of them include in config mode.

o unprivileged mode :

Router>

o privileged mode :

Router#

o config mode :

Router(config)#

From unprivileged to privileged use enable command and need enable password / secret password if set, go back to unprivileged mode type disable. To access config mode must from privileged mode just type config terminal or just conf t and go in Router(config)#, go back to privileged mode type exit.

In early IOS cisco build, config mode just for config if we need to show or execute command, must be exit from config mode, but in newer IOS version we can do execute command from config mode using 'do' command in every execute command.

Router#configure ?
  memory             Configure from NV memory
  network            Configure from a TFTP network host
  overwrite-network  Overwrite NV memory from TFTP network host
  terminal           Configure from the terminal
  

Router#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#do ?
  LINE  Exec Command
  
Router(config)#do sh ver
Cisco Internetwork Operating System Software 
IOS (tm) xxxx Software (xxxx), Version 12.2(13)T5,  RELEASE SOFTWARE (fc1)
TAC Support: http://www.cisco.com/tac
Copyright (c) 1986-2003 by cisco Systems, Inc.
Compiled Wed 28-May-03 16:33 by nmasa

This feature like in JUNOS, Juniper OS using 'run' command in edit mode to execute comamnd, but I don't know much more detail about management mode in JUNOS, just compared.

> edit 
Entering configuration mode

[edit]
# run show configuration 
...
version 7.1R2.2;
groups {
    21;
}
...