man -k bash; # search for bash in all man-pages
bash (1)             - GNU Bourne-Again SHell
bash-builtins (7)    - bash built-in commands, see bash(1)
bashbug (1)          - report a bug in bash
builtins (7)         - bash built-in commands, see bash(1)
dh_bash-completion (1) - install bash completions for package
rbash (1)            - restricted bash, see bash(1)
root@debian:/home/user#


suse:~ # whatis crontab
crontab (1)          - maintains crontab files for individual users
crontab (5)          - files used to schedule the execution of programs
crontab (1p)         - schedule periodic background work
suse:~ # man 5 crontab; # show manpage 5

apropos fdisk; #  search the manual page names and descriptions
cfdisk (8)           - display or manipulate a disk partition table
fdisk (8)            - manipulate disk partition table
sfdisk (8)           - partition table manipulator for Linux

manpath; # where are manpages stored?
uname -a ; # tested with
Linux debian 3.16.0-4-686-pae #1 SMP Debian 3.16.43-2 (2017-04-30) i686 GNU/Linux
/usr/local/man:/usr/local/share/man:/usr/share/man

manpath; uname -a ; # tested with
/usr/local/share/man:/usr/share/man
Linux centos 3.10.0-514.el7.x86_64 #1 SMP Tue Nov 22 16:42:41 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

echo $MANPATH; uname -a ; # tested with
/usr/local/man:/usr/share/man
Linux suse 4.4.21-69-default #1 SMP Tue Oct 25 10:58:20 UTC 2016 (9464f67) x86_64 x86_64 x86_64 GNU/Linux
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