Is there any way to copy all lines from open file to clipboard in VI editor. I tried yG but it's not using clipboard to store those lines.
So is it possible?
You should yank the text to the * or + registers:
gg"*yG
Explanation:
gg to get the cursor to the first character of the file"*y to start a yank command to the register * from the first line, until...G to go the end of the file