Alan, the first answer of this stackoverflow’s topic is really the best one ;-))

Indeed ! At first sight, although that, in OP text , word CAT always precedes the word DOG, I thought about the search regex, below :

^.*(CAT).*(DOG).*|^.*(?2).*(?1).*

However, the syntax ^(?=.*CAT)(?=.*DOG).* is really more elegant !

We can generalize to any number of words and, also, add conditions which should not occur ;-)) . For instance, the following regex would match all lines, with their line-breaks, which :

• Contain the 3 expressions WORD_1 AND WORD_2 AND WORD_5

• Does NOT contain the 2 expressions WORD_4 OR WORD_6

(?-s)^(?=.*WORD_1)(?=.*WORD_2)(?=.*WORD_5)(?!.*WORD_4)(?!.*WORD_6).*\R

So, it matches the lines 5, 12 and 14, only, in the text :

This line   1  contains   WORD_1  WORD_2
This line   2  contains   WORD_1  WORD_3  WORD_5
This line   3  contains   WORD_3  WORD_5  WORD_4
This line   4  contains   WORD_1  WORD_5
This line   5  contains   WORD_5  WORD_2  WORD_1
This line   6  contains   WORD_2  WORD_1  WORD_6  WORD_5
This line   7  contains   WORD_4  WORD_1  WORD_5
This line   8  contains   WORD_2
This line   9  contains   WORD_5  WORD_2  WORD_4  WORD_7  WORD_1
This line  10  contains   WORD_1  WORD_6  WORD_2
This line  11  contains   WORD_4  WORD_2  WORD_1, WORD_5  WORD_6
This line  12  contains   WORD_7  WORD_2  WORD_5  WORD_1
This line  13  contains   WORD_6  WORD_2  WORD_1  WORD_5
This line  14  contains   WORD_1  WORD_5  WORD_8  WORD_2  WORD_3

Best Regards,

guy038

Do you know how to use google?

If not, then: https://stackoverflow.com/questions/4389644/regex-to-match-string-containing-two-names-in-any-order