I was able to match everything outside the square brackets using ([^\[\]]+)(?:$|(?=\[)), which gives me:

!Bat_Boy.png|thumbnail! !visagepaume.png|thumbnail!, Test comment: public., Test comment: internal., [^TEST_ATTACHMENT.txt], Test comment: public!, !visagepaume.png|thumbnail!, Test comment: internal!, [^TEST_ATTACHMENT.txt]

Is there a way to write a single regex that would also match outside two exclamation marks with a pipe in-between, in addition? This is to be used with a single java string replaceAll() method. Basically, I am looking for this result:

!Bat_Boy.png|thumbnail! !visagepaume.png|thumbnail!, Test comment: public., Test comment: internal., [^TEST_ATTACHMENT.txt], Test comment: public!, !visagepaume.png|thumbnail!, Test comment: internal!, [^TEST_ATTACHMENT.txt]

Notes:

• I am including the pipe in-between as a requirement mainly because there could be exclamation marks in those "test comments", and I thought maybe this would help.
• Don't think I need to worry about nesting [] or !