现在才刚知道在RedHat Linux下修改MANPATH不是用的$MANPATH而是修改/etc/man.config，比较惭愧
root@nbu-server etc]# vi /etc/man.config
#
# Generated automatically from man.conf.in by the
# configure script.
#
# man.conf from man-1.5o1
#
# For more information about this file, see the man pages man(1)
# and man.conf(5).
#
# This file is read by man to configure the default manpath (also used
# when MANPATH contains an empty substring), to find out where the cat
# pages corresponding to given man pages should be stored,
# and to map each PATH element to a manpath element.
# It may also record the pathname of the man binary. [This is unused.]
# The format is:
#
# MANBIN pathname
# MANPATH manpath_element [corresponding_catdir]
# MANPATH_MAP path_element manpath_element
#
# If no catdir is given, it is assumed to be equal to the mandir
# (so that this dir has both man1 etc. and cat1 etc. subdirs).
# This is the traditional Unix setup.
# Certain versions of the FSSTND recommend putting formatted versions
# of /usr/.../man/manx/page.x into /var/catman/.../catx/page.x.
# The keyword FSSTND will cause this behaviour.
# Certain versions of the FHS recommend putting formatted versions of
# /usr/.../share/man/[locale/]manx/page.x into
# /var/cache/man/.../[locale/]catx/page.x.
# The keyword FHS will cause this behaviour (and overrides FSSTND).
# Explicitly given catdirs override.
#
# FSSTND
FHS
#
# This file is also read by man in order to find how to call nroff, less, etc.,
# and to determine the correspondence between extensions and decompressors.
#
# MANBIN /usr/local/bin/man
#
# Every automatically generated MANPATH includes these fields
#
MANPATH /usr/share/man
MANPATH /usr/man
MANPATH /usr/local/share/man
MANPATH /usr/local/man
MANPATH /usr/X11R6/man
MANPATH /usr/openv/man
。。。
