使用sed或awk在第6个逗号后添加了一个字符

Question

我有一个如下的csv文件：

last,first,A00XXXXXX,1888-01-01,2015-05-13,Elementary Algebra 34,
last,first,A00XXXXXX,1888-01-01,2015-05-13,Reading Comprehension 97,Sentence Skills 104,College Level Math 76,Elementary Algebra 115,

如果该行中不存在“阅读理解”这一短语，请在第5个逗号后添加逗号

我试图用AWK来解决这个问题，但似乎无法弄明白。我假设我需要使用gsub循环，但我无法弄清楚如何在$ 5之后添加'，'

最终目标如下：

last,first,A00XXXXXX,1888-01-01,2015-05-13,,Elementary Algebra 34,
last,first,A00XXXXXX,1888-01-01,2015-05-13,Reading Comprehension 97,Sentence Skills 104,College Level Math 76,Elementary Algebra 115,

Answer 1

使用sed：

sed '/Reading Comprehension/! s/,/,,/5'

使用awk：

awk -F, -v OFS=, '!/Reading Comprehension/ { $5 = $5 "," } 1'

输出：

last,first,A00XXXXXX,1888-01-01,2015-05-13,,Elementary Algebra 34,
last,first,A00XXXXXX,1888-01-01,2015-05-13,Reading Comprehension 97,Sentence Skills 104,College Level Math 76,Elementary Algebra 115,