I am connected from windows to linux using Putty. I have a file result.csv I want to copy all the text from this file to windows clipboard and then paste the text to a notepad? Please help me.
So my suggestion would be to copy the file to your local computer using scp instead. If you have ssh working then you should have the possibility to connect with scp.
Try using a program called winscp
Nano is a terminal application, so it doesn't have cross-application copy-paste, only an internal clipboard.
It's possible to copy a file to the clipboard on a Linux machine, but that requires a GUI (an X server), you can't do that with a pure text connection. You can actually use PuTTY to make a text+graphics connection by activating X11 forwarding, but that requires additional software on the Windows side, because Windows doesn't support X11. If you want to do that, see How to use X11 forwarding with PuTTY or Installing/Configuring PuTTy and Xming or X11 Forwarding using Xming and PuTTY. Then you can use
xsel -b <myfile.txt or
xclip <myfile.txt to copy the content of
myfile.txt to the clipboard.
Alternatively, you can use the PuTTY companion programs PSFTP and PSCP to copy files.
If you have a file open in nano in a putty window, you will have to turn off mouse support (Alt-M will toggle). After that, you can select text in nano with the left mouse drag. Then left-click on the selected text to copy it to the windows clipboard. Anywhere you can now paste that clipboard text with a right-click. I often use this method to copy a single command from a bash script file, open in nano, to the bash command line to execute.