How to login without any connection in sqlplus?

CMD> sqlplus /nolog
SQL> conn hr/hr

- nolog parameter is using for just entering to sqlplus

How to prevent auto-closing for CMD ?

To do that, you may add "pause" command into your .bat file as you wish.

Example;
sc config OracleServiceXE start= auto
sc start OracleServiceXE
sc config OracleXETNSListener start= auto
sc start OracleXETNSListener
rem stop cmd
pause

How to use tftpd32 tool ?

You may use tftp (trial file transfer protocol) for transfering documents or files between Linux and Windows.

To do that, at first, you should configure tftp tool.

Please follow the steps:
Click Settings:
Only activate TFTP Server box in Global tab
Configure Current Directory in TFTP tab
Activate "Bind TFTP to this address (Server_Host_IP)" -> Server_Host_IP could be selected as your machine local IP

An Example:
A machine is Windows
B machine is Linux
tftp server is installed in Windows

Run following commands In linux machine (B):
-> tftp
-> get mytext.txt
-> put mytextnew.txt

get: to transfer file from Windows to Linux machine
put; to transfer file from linux to windows machine