send man page to text file

Printing a manpage to a text file (perhaps more portable for cross-platform or bedtime reading):

generic Unix/Linux, using `col`:
man rcs | col -b > /tmp/man_rcs.txt

These alternatives would require that you reset PAGER or MANPAGER:
alternative BSD :
export MANPAGER=cat
man pf.conf > man_pf.conf.txt

alternative BSD :
export PAGER=cat
man pf.conf > man_pf.conf.txt

Ubuntu, Debian, Mint, etc. allow all of these alternatives:

-P pager, --pager=pager
Specify which output pager to use. By default, man uses pager -s. This option overrides the $MANPAGER environment variable, which in turn overrides the $PAGER environment variable. It is not used in conjunction with -f or -k.