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.
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.
1.这里只是把空格当成了分隔符，如果含有标点符号，还需要把标点符号考虑进去
2.注意sort对出现次数进行排序时需要指定参数-n，表示使用数值方式排序，默认是字符方式(“10”<"2")
cat words.txt | tr ‘ ‘ ‘\n‘|sort|sed ‘/^$/d‘|awk ‘{a[$1]++}END{for(item in a)print item,a[item]}‘|sort -k 2 -rn
原文：http://www.cnblogs.com/chybot/p/4486703.html