如何清除配置文件

R1841#erase ?
/all Erase all files(in NVRAM)
/no-squeeze-reserve-space Do not reserve space for squeeze operation
nvram: Filesystem to be erased
startup-config Erase contents of configuration memory

R1841#write ?
core Write Core File
erase Erase NV memory
memory Write to NV memory
mib-data Write MIB persistence data to NV memory
network Write to network TFTP server
terminal Write to terminal

R1841#erase startup-config
Erasing the nvram filesystem will remove all configuration files! Continue? [confirm]
[OK]
Erase of nvram: complete

直接重启机器（开关电源）
--- System Configuration Dialog ---

Would you like to enter the initial configuration dialog? [yes/no]: n

Press RETURN to get started!

*Jun 3 05:27:04.227: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down
*Jun 3 05:27:04.367: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down
*Jun 3 05:30:47.439: %IP-5-WEBINST_KILL: Terminating DNS process
*Jun 3 05:30:48.579: %LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down
*Jun 3 05:30:48.579: %LINK-5-CHANGED: Interface FastEthernet0/1, changed state to administratively down
*Jun 3 05:30:53.759: %SYS-5-RESTART: System restarted --
Cisco IOS Software, 1841 Software (C1841-IPBASE-M), Version 12.4(15)T10, RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2009 by Cisco Systems, Inc.
Compiled Mon 14-Sep-09 12:41 by prod_rel_team
*Jun 3 05:30:53.763: %SNMP-5-COLDSTART: SNMP agent on host Router is undergoing a cold start
Router>
Router>en
Router#conf t
Enter configuration commands, one per line. End with CNTL/Z.