In [1]:

    

#!/usr/bin/env bash


    

In [16]:

    

NUMCOUNT=$1
#copy first parameter to NUMCOUNT


    

In [17]:

    

echo "A S D F G" | tr '[:lower:]' '[:upper:]'
#[:lower:] all lower character
#[:upper:] all upper case
#tr: translate [:lower:] into [:upper:]


    

    




A S D F G

In [10]:

    

echo "a b c d d d sdf dsf " | grep -oE '\w+'
#grep -o: show only matched item
#grep -E:egrep


    

    




a
b
c
d
d
d
sdf
dsf

In [11]:

    

echo "a b c d d d sdf dsf " | grep -oE '\w+' | sort | uniq -c
#uniq :delete repeated item. -c :count


    

    




      1 a
      1 b
      1 c
      3 d
      1 sdf
      1 dsf

In [14]:

    

echo "a b c d d d sdf dsf " | grep -oE '\w+' | sort | uniq -c | sort -hr
#sort -h:sort by human way -r: reverse order


    

    




      3 d
      1 sdf
      1 dsf
      1 c
      1 b
      1 a

In [15]:

    

echo "a b c d d d sdf dsf " | grep -oE '\w+' | sort | uniq -c | sort -hr | head -n 3
#display top 3 lines


    

    




      3 d
      1 sdf
      1 dsf

In [ ]:

    

echo "a b c d d d sdf dsf " | grep -oE '\w+' | sort | uniq -c | sort -hr | head -n $NUMCOUNT