在两个词之间提取数据Linux脚本

Question

I have data in a file as shown below and need to extract the string between PER*IC and ~ PER*IC*FBI DEPT*EM*~

I tried this: grep -P -o '(?<=PER*IC).*?(?=~)' inputfile but am getting an error message:

grep: lookbehind assertion is not fixed length

When i tried grep -P -o '(?<=PER).*?(?=~)' inputfile it produces the output: *IC*FBI DEPT*EM*

I want to include PER*IC as start of string in code and expected result is *FBI DEPT*EM*

Answer 1

In '(?<=PER*IC).*?(?=~)' the '*' is a repetition character that will match zero or more 'R' characters. You need a literal '*' which can be done by including it within a character class, eg [*] making your expression:

grep -P -o '(?<=PER[*]IC).*?(?=~)'

Which would return:

*FBI DEPT*EM*