sed -i command for in-place editing to work with both GNU sed and BSD/OSX

Question

I\'ve got a makefile (developed for gmake on Linux) that I\'m attempting to port to MacOS, but it seems like sed doesn\'t want to cooperate. What I

Answer 1

The currently accepted answer is flawed in two very important ways.

1. With BSD sed (the OSX version), the -e option is interpreted as a file extension and therefore creates a backup file with a -e extension.

2. Testing for the darwin kernel as suggested is not a reliable approach to a cross platform solution since GNU or BSD sed could be present on any number of systems.

A much more reliable test would be to simply test for the --version option which is only found in the GNU version of sed.

sed --version >/dev/null 2>&1

Once the correct version of sed is determined, we can then execute the command in its proper syntax.

GNU sed syntax for -i option:

sed -i -- "$@"

BSD sed syntax for -i option:

sed -i "" "$@"

Finally put it all together in a cross platform function to execute an in place edit sed commend:

sedi () {
    sed --version >/dev/null 2>&1 && sed -i -- "$@" || sed -i "" "$@"
}

Example usage:

sedi 's/old/new/g' 'some_file.txt'

This solution has been tested on OSX, Ubuntu, Freebsd, Cygwin, CentOS, Red Hat Enterprise, & Msys.