Use the contents of a file to replace a string using SED

Question

What would be the sed command for mac shell scripting that would replace all iterations of string \"fox\" with the entire string content of myFile.txt.

myFile.txt wo

Answer 1

You can use the r command. When you find a 'fox' in the input...

/fox/{

...replace it for nothing...

    s/fox//g

...and read the input file:

    r f.html
}

If you have a file such as:

$ cat file.txt
the
quick
brown
fox
jumps
over
the lazy dog
fox dog

the result is:

$ sed '/fox/{
    s/fox//g
    r f.html
}' file.txt
the
quick
brown

    </div>
  </div>
  <br>
  <div id="container2">
    <div class="question" onclick="javascript:show('answer2')";>
jumps
over
the lazy dog
 dog
    </div>
  </div>
  <br>
  <div id="container2">
    <div class="question" onclick="javascript:show('answer2')";>

EDIT: to alter the file being processed, just pass the -i flag to sed:

sed -i '/fox/{
    s/fox//g
    r f.html
}' file.txt

Some sed versions (such as my own one) require you to pass an extension to the -i flag, which will be the extension of a backup file with the old content of the file:

sed -i.bkp '/fox/{
    s/fox//g
    r f.html
}' file.txt

And here is the same thing as a one liner, which is also compatible with Makefile

sed -i -e '/fox/{r f.html' -e 'd}'

Answer 2

Ultimately what I went with which is a lot simpler than a lot of solutions I found online:

str=xxxx
sed -e "/$str/r FileB" -e "/$str/d" FileA

Supports templating like so:

str=xxxx
sed -e "/$str/r $fileToInsert" -e "/$str/d" $fileToModify