command: whatis
usage: it displays a single line information about a command
syntax: $ whatis [option] keyword
example:
1. To emit debugging messages of ls command
$ whatis -d ls
2. To print verbose warning messages
$ whatis -v ps
3. To search only these sections of keyword
$ whatis -s "1","8" keyword
4. To print the keywords contain wildcards
$ whatis -w 'bc*'
5. To interpret each keyword as regex
$ whatis -r '^bc'
it displays linux commands start from 'bc'
$ whatis -r 'ee$'
it displays linux commands ends with 'ee'
6. To disable trimmed output
$ whatis -l tee
7. To print help info of this command
$ whatis -h
8. To set search path for manual pages to path
$ whatis -M /usr/share/man ps
regards,
dhanasekar