$ cat janne.txt
This is a test.
This is only a test.
Had this been an actual emergency, the attention signal you just heard would have been followed by news or instructions.
This has been a test.
$
$ perl 11104497.pl janne.txt
Had                             1
This                            3
a                               3
actual                          1
an                              1
attention                       1
been                            3
by                              1
emergency,                      1
followed                        1
has                             1
have                            1
heard                           1
instructions.                   1
is                              2
just                            1
news                            1
only                            1
or                              1
signal                          1
test.                           3
the                             1
this                            1
would                           1
you                             1
These are the 10 most frequented words of janne.txt :
a occured 3 times
This occured 3 times
been occured 3 times
test. occured 3 times
is occured 2 times
has occured 1 times
or occured 1 times
news occured 1 times
by occured 1 times
this occured 1 times

$