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

<

Answer 1

If you are doing pattern matching first, e.g.,

/pattern/s/xx/yy/g

then you want to put the I after the pattern:

/pattern/Is/xx/yy/g

Example:

echo Fred | sed '/fred/Is//willma/g'

returns willma; without the I, it returns the string untouched (Fred).

Answer 2

^{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