Recursive search and replace in text files on Mac and Linux

OS X uses a mix of BSD and GNU tools, so best always check the documentation (although I had it that less didn't even conform to the OS X manpage):

https://web.archive.org/web/20170808213955/https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man1/sed.1.html

sed takes the argument after -i as the extension for backups. Provide an empty string (-i '') for no backups.

The following should do:

LC_ALL=C find . -type f -name '*.txt' -exec sed -i '' s/this/that/ {} +

The -type f is just good practice; sed will complain if you give it a directory or so.-exec is preferred over xargs; you needn't bother with -print0 or anything.The {} + at the end means that find will append all results as arguments to one instance of the called command, instead of re-running it for each result. (One exception is when the maximal number of command-line arguments allowed by the OS is breached; in that case find will run more than one instance.)

For the mac, a more similar approach would be this:

find . -name '*.txt' -print0 | xargs -0 sed -i "" "s/form/forms/g"

As an alternative solution, I'm using this one on Mac OSX 10.7.5

grep -ilr 'old-word' * | xargs -I@ sed -i '' 's/old-word/new-word/g' @

Credit goes to: Todd Cesere's answer