shell脚本单词统计问题

Question

编写Shell脚本test3.sh. 假设存在一文本文件a.txt, 完成以下功能:

生成count.txt文件, 该文件记录了a.txt文件中出现的单词及其出现次数, 按出现次数的降序排序.

Answer 1

#! /bin/bash

filename=a.txt
output_filename=count.txt
grep -E -o "\b[[:alpha:]]+\b" $filename | awk ' { count[$0]++ }
END{printf("%-20s%s\n","Word","Count");
for(word in count)
{printf("%-20s%s\n",word,count[word])}
}' >> $output_filename