I want to print a man page for a command in unix, this is what I did

man command > command.txt

but when I view the output file command.txt I found there are lot of _^H characters that in the man page are actually underline character, how can I replace this _^H with underline character?

Thank you for any advise!

That _^H is the underline character followed by a backspace character. Most printers will allow something like "_^Hx" which results in a underlined x. But in vi you will see the actual characters.

If you want a man page that looks good in vi, you want to delete the underlines. Here is a way:
man command | col -b > command.txt

Hi Perderabo, thank you very much, the output file looks good in vi now. thanks.