Case-insensitive search and replace with sed

Question

I\'m trying to use SED to extract text from a log file. I can do a search-and-replace without too much trouble:

sed \'s/foo/bar/\' mylog.txt

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Answer 1

^{Editor's note: This solution doesn't work on macOS (out of the box), because it only applies to GNU sed, whereas macOS comes with BSD sed.}

Capitalize the 'I'.

sed 's/foo/bar/I' file