How to replace paired square brackets with other syntax with sed?

Question

I want to replace all pairs of square brackets in a file, e.g., [some text], with \\macro{some text}, e.g.:

This is some [text].
Th         


        

Answer 1

sed -e 's/\[\([^]]*\)\]/\\macro{\1}/g' file.txt

This looks for an opening bracket, any number of explicitly non-closing brackets, then a closing bracket. The group is captured by the parens and inserted into the replacement expression.