### 192. Word Frequency

Write a bash script to calculate the frequency of each word in a text file words.txt.

For simplicity sake, you may assume:

• words.txt contains only lowercase characters and space ' ' characters.
• Each word must consist of lowercase characters only.
• Words are separated by one or more whitespace characters.

For example, assume that words.txt has the following content:

the day is sunny the the
the sunny is is

Your script should output the following, sorted by descending frequency:
the 4
is 3
sunny 2
day 1


Note:
Don't worry about handling ties, it is guaranteed that each word's frequency count is unique.

[show hint]

Hint:
Could you write it in one-line using Unix pipes?

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