所以，我不确定我的系统（ubuntu 12.04）出了什么问题，但我的手册页似乎不起作用。我尝试 man gcc 并得到以下响应
没有 gcc 的手册条目当手册页不可用时，请参阅“man 7 undocumented”以获取帮助。
但是我看到 /usr/share/man/man1/gcc.1.gz 中的 man 条目
以下是我的 /etc/manpath.config 文件的样子
# manpath.config
#
# This file is used by the man-db package to configure the man and cat paths.
# It is also used to provide a manpath for those without one by examining
# their PATH environment variable. For details see the manpath(5) man page.
#
# Lines beginning with `#' are comments and are ignored. Any combination of
# tabs or spaces may be used as `whitespace' separators.
#
# There are three mappings allowed in this file:
# --------------------------------------------------------
# MANDATORY_MANPATH manpath_element
# MANPATH_MAP path_element manpath_element
# MANDB_MAP global_manpath [relative_catpath]
#---------------------------------------------------------
# every automatically generated MANPATH includes these fields
#
#MANDATORY_MANPATH /usr/src/pvm3/man
#
MANDATORY_MANPATH /usr/man
MANDATORY_MANPATH /usr/share/man
MANDATORY_MANPATH /usr/local/share/man
#---------------------------------------------------------
# set up PATH to MANPATH mapping
# ie. what man tree holds man pages for what binary directory.
#
# *PATH* -> *MANPATH*
#
MANPATH_MAP /bin /usr/share/man
MANPATH_MAP /usr/bin /usr/share/man
MANPATH_MAP /sbin /usr/share/man
MANPATH_MAP /usr/sbin /usr/share/man
MANPATH_MAP /usr/local/bin /usr/local/man
MANPATH_MAP /usr/local/bin /usr/local/share/man
MANPATH_MAP /usr/local/sbin /usr/local/man
MANPATH_MAP /usr/local/sbin /usr/local/share/man
MANPATH_MAP /usr/X11R6/bin /usr/X11R6/man
MANPATH_MAP /usr/bin/X11 /usr/X11R6/man
MANPATH_MAP /usr/games /usr/share/man
MANPATH_MAP /opt/bin /opt/man
MANPATH_MAP /opt/sbin /opt/man
#---------------------------------------------------------
# For a manpath element to be treated as a system manpath (as most of those
# above should normally be), it must be mentioned below. Each line may have
# an optional extra string indicating the catpath associated with the
# manpath. If no catpath string is used, the catpath will default to the
# given manpath.
#
# You *must* provide all system manpaths, including manpaths for alternate
# operating systems, locale specific manpaths, and combinations of both, if
# they exist, otherwise the permissions of the user running man/mandb will
# be used to manipulate the manual pages. Also, mandb will not initialise
# the database cache for any manpaths not mentioned below unless explicitly
# requested to do so.
#
# In a per-user configuration file, this directive only controls the
# location of catpaths and the creation of database caches; it has no effect
# on privileges.
#
# Any manpaths that are subdirectories of other manpaths must be mentioned
# *before* the containing manpath. E.g. /usr/man/preformat must be listed
# before /usr/man.
#
# *MANPATH* -> *CATPATH*
#
MANDB_MAP /usr/man /var/cache/man/fsstnd
MANDB_MAP /usr/share/man /var/cache/man
MANDB_MAP /usr/local/man /var/cache/man/oldlocal
MANDB_MAP /usr/local/share/man /var/cache/man/local
MANDB_MAP /usr/X11R6/man /var/cache/man/X11R6
MANDB_MAP /opt/man /var/cache/man/opt
#
#---------------------------------------------------------
# Program definitions. These are commented out by default as the value
# of the definition is already the default. To change: uncomment a
# definition and modify it.
#
#DEFINE pager pager -s
#DEFINE cat cat
#DEFINE tr tr '\255\267\264\327' '\055\157\047\170'
#DEFINE grep grep
#DEFINE troff groff -mandoc
#DEFINE nroff nroff -mandoc
#DEFINE eqn eqn
#DEFINE neqn neqn
#DEFINE tbl tbl
#DEFINE col col
#DEFINE vgrind vgrind
#DEFINE refer refer
#DEFINE grap grap
#DEFINE pic pic -S
#
#DEFINE compressor gzip -c7
#---------------------------------------------------------
# Misc definitions: same as program definitions above.
#
#DEFINE whatis_grep_flags -i
#DEFINE apropos_grep_flags -iEw
#DEFINE apropos_regex_grep_flags -iE
#---------------------------------------------------------
# Section names. Manual sections will be searched in the order listed here;
# the default is 1, n, l, 8, 3, 0, 2, 5, 4, 9, 6, 7. Multiple SECTION
# directives may be given for clarity, and will be concatenated together in
# the expected way.
# If a particular extension is not in this list (say, 1mh), it will be
# displayed with the rest of the section it belongs to. The effect of this
# is that you only need to explicitly list extensions if you want to force a
# particular order. Sections with extensions should usually be adjacent to
# their main section (e.g. "1 1mh 8 ...").
#
SECTION 1 n l 8 3 2 3posix 3pm 3perl 5 4 9 6 7
#
#---------------------------------------------------------
# Range of terminal widths permitted when displaying cat pages. If the
# terminal falls outside this range, cat pages will not be created (if
# missing) or displayed.
#
#MINCATWIDTH 80
#MAXCATWIDTH 80
#
# If CATWIDTH is set to a non-zero number, cat pages will always be
# formatted for a terminal of the given width, regardless of the width of
# the terminal actually being used. This should generally be within the
# range set by MINCATWIDTH and MAXCATWIDTH.
#
#CATWIDTH 0
#
#---------------------------------------------------------
# Flags.
# NOCACHE keeps man from creating cat pages.
#NOCACHE
感谢您的帮助（ps 即使'man man'也失败了）
编辑：当我运行时，ls -l /usr/share/man/man1/gcc*我得到以下输出
lrwxrwxrwx 1 root root 12 May 27 15:41 /usr/share/man/man1/gcc.1.gz -> gcc-4.6.1.gz
-rw-r--r-- 1 root root 217776 Apr 15 17:34 /usr/share/man/man1/gcc-4.6.1.gz
答案1
经过一夜的艰苦努力，我终于发现问题出在 perl 上。清除并重新安装 perl 后，它现在修复了我的手册页。感谢大家的帮助，至少现在我对 man 到底做了什么有了更好的理解 ;-)