leetcode Word Frequency

题目连接地址：https://leetcode.com/problems/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.

 代码：

# Read from the file words.txt and output the word frequency list to stdout.
tr -s "	| " "
" <words.txt|sort |uniq -c | sort -k1 -r|awk '{print $2,$1}'

解释：

tr -s " | " " " <words.txt	|sort	|uniq -c	| sort -k1 -r	|awk '{print $2,$1}'
将文件里面的tab或者空格统一替换成换行	排序	去重，并且显示 每个单词出现的数量	按照单词出现的数量 进行逆序排序	交换第一列和第二列的位置 （因为uniq出来的结果数量是在前面的）