Did `man ls > temp.txt`. Output textfile is corrupted
From man man:

To get a plain text version of a man page, without backspaces and underscores, try
    # man foo | col -b &gt; foo.mantxt


man prints formatted version of man page, underscores and double letters are parsed

Its not so much that they are 'parsed' but rather &quot;if you don't have a terminal, bold format is to be displayed as a repeated character&quot;. Once you hook it up to a terminal (vt100, xterm, Terminal, etc...), man recognizes the terminal and sends the appropriate control codes to do color, bold, underline and the like. Its being parsed correctly - just for a null terminal type.

 comment by MichaelT