Check if the pattern exists in the file, evaluate if

I want to check if a template exists in a file.

• If the template exists (in the file among the list), replace and update the corresponding file.
• If the template doesn't exist, do nothing.

So far I have done:

    if [ -f $((`awk '/Pattern1/' $FILE`))];then
        sed 's/Pattern1/\nWORD/g' $FILE > a
        mv a $FILE
    fi

      

        
        
        
      

    

But, when I test it, I get the following error:

syntax error: invalid arithmetic operator

      

        
        
        
      

    

And I don't want to evaluate the numeric part, just if the pttern ~ string is there or not.

File input 1

Rho =  1.1955904623E+02     Rho at Nucleus =  1.1955904594E+02

      

        
        
        
      

    

File input2

Rho =  1.1955904623E+02