Sed to make global replacements.

[Gregory A. Hooten]

I am working with sed on a file, and need to make a global replacement, but 
what I am replacing are special characters to sed.  I do not know how to 
replace them.  

I would like to change the characters \(12 to 1/2, but every thing I try
thinks the \( is the start of a character group.  I would like any help 
possible on this problem.  

Thanks.

Greg Hooten
GAHOOTEN at ames.arc.nasa.gov