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

题意：给出一个文件，输出每个单词及出现频率

思路：用awk，其中的数组是key-value形式

awk '{words[$1]+=1} END{for (word in words) {print word, words[word]}}' RS="[ \n]+" words.txt | sort -nrk2