Different router modes are explained in below fig.
copy running-configuration startup -configuration (alternatively, you can use an older version of the command, WRITE MEMORY): This command saves the current configuration to NVRAM.
Alternatively, we can issue the command using short form as below
copy running startup - Copies configuration from RAM to NVRAM
copy startup-config running-config - This command merges configuration from NVRAM to RAM.
copy flash tftp - Copies current IOS from router flash memory to TFTP server.
copy tftp flash - Copies image file from TFTP server to flash. This is used to upgrade the IOS image file to a newer version, or if your IOS image becomes corrupt.
copy running-config tftp - Copy running configuration file to TFTP server
copy tftp: startup-config - This command is useful to restore the startup-config file incase the original is lost or corrupt. The command loads the startup-config file from a remote tftp server.
The following are some important commands that can be used to edit and review command history buffer. It will be useful to practice these commands.
<ctrl> A : Move to the beginning of the command line
<ctrl> E : Move to the end of the command line
<ctrl> F : Move forward one character, same as using "Right Arrow".
<ctrl> B : Move backward one character, same as using "Left Arrow".
<ctrl> P : Repeat Previous command, same as using "Up Arrow".
<ctrl> N : Repeat Next (more recent) command, same as using "Down Arrow".
<esc> B : Moves to beginning of previous word.
<esc> F : Moves to beginning of next word.
<ctrl>R : Creates new command prompt, followed by all the characters typed at the last one.