sed command with -i option failing on Mac, but works on Linux

I've successfully used the following sed command to search/replace text in Linux:

sed -i 's/old_link/new_link/g' *

However, when I try it on my Mac OS X, I get:

"command c expects \ followed by text"

I thought my Mac runs a normal BASH shell. What's up?


According to @High Performance, this is due to Mac sed being of a different (BSD) flavor, so my question would therefore be how do I replicate this command in BSD sed?


Here is an actual example that causes this:

sed -i 's/hello/gbye/g' *


  • The -i option (alternatively, --in-place) means that you want files edited in-place, rather than streaming the change to a new place.

    Modifying a file in-place suggests a need for a backup file - and so a user-specified extension is expected after -i, but the parsing of the extension argument is handled differently under GNU sed & Mac (BSD) sed:

    So GNU & Mac will interpret this differently:

    sed -i 's/hello/bye/g' jkl.txt

    Portable solution

    To get a portable command, you can use this invocation, that works across both GNU sed and Mac (BSD) sed in Mac OS X Mavericks (v10.9, released June 2013) and above:

    sed -i'' -e 's/hello/bye/g' jkl.txt

    Placing the extension immediately after the -i (eg -i'' or -i'.bak', without a space) is what GNU sed expects, and is now accepted by Mac (BSD) sed too, though it wasn't tolerated by earlier versions (eg with Mac OS X v10.6, a space was required after -i, eg -i '.bak').

    The -e parameter allows us to be explicit about where we're declaring the edit command.

    Until Mac OS was updated in 2013, there wasn't any portable command across GNU and Mac (BSD), as these variants also failed:

    When there wasn't a sed command working on all platforms, you could have tried using another command to achieve the same result, e.g. perl -i -pe's/old_link/new_link/g' *.