title: issue on macos while breaking an expression in several lines through sed
body: <p>I am cutting an expression after 135 characters and printing each line starting with + or - through the command</p>
  
  <pre><code>cat file1 | tr -d '\n' &gt; file2
  sed 's/\(\(.\)\{,135\}\) \([\+\-]\)/\1\n\3/g' file2 &gt; file3
  </code></pre>
  
  <p>cat file1</p>
  
  <pre><code>(-128*r1*T6*y*(22*y^3 + 32*y^2*(-1 + z) + 33*y*(-1 + z)^2 + 12*(-1 + z)^3))/
    3 - (128*r1*T2*y*(11*y^3 - 2*y^2*z - 3*y*z^2 - 12*z^3))/3 +
   (128*r1*T3*z*(12*y^3 + 3*y^2*z + 2*y*z^2 - 11*z^3))/3 -
   2816*r1*T1*(y^4 + 2*y^3*(-1 + z) + 3*y^2*(-1 + z)^2 + 2*y*(-1 + z)^3 +
    (1 - z + z^2)^2) + (256*r1*T5*(11 + 11*y^4 + 14*z - 14*y^3*z - 36*z^2 +
   44*z^3 - 22*z^4 - 6*y^2*z*(-7 + 6*z) - 2*y*z*(21 - 36*z + 22*z^2)))/3 +
   (128*r1*T8*(110 + 99*y^4 - 174*z + 261*z^2 - 164*z^3 + 99*z^4 +
    2*y^3*(-82 + 81*z) + 3*y^2*(87 - 172*z + 86*z^2) +
    6*y*(-29 + 86*z - 86*z^2 + 27*z^3)))/3
  </code></pre>
  
  <p>This works on linux, however does not in mac. The error is showing is the following</p>
  
  <pre><code>sed: 1: "s/\(\(.\)\{,135\}\) \([ ...": RE error: invalid repetition count(s) 
  </code></pre>
  
  <p>Any way out to fix this?</p>