omit filenames in grep

Question

I am greping a string from multiple files, but the one undesired side effect, is the filename prefacing the output. How can I suppress the filename outputs using only grep?

  $ grep -i lp lpNet* 
    lpNet:This was printed via the internet using the lp command.
    lpNet:I believe lp doesnt care what the device is. 
    lpNet1:This was printed via the internet using the lp command.
    lpNet1:I believe lp doesnt care what the device is. 
    lpNet2:This was printed via the internet using the lp command.
    lpNet2:I believe lp doesnt care what the device is. 
    lpNet3:This was printed via the internet using the lp command.
    lpNet3:I believe lp doesnt care what the device is. 

I have solved the issue for now using cat lpNet* | grep lp I am just wondering if there is a more efficient path to have the same effect

Solution

The default behavior is to print the filename when given multiple file arguments - to suppress this, you can add the -h or --no-filename option

From the Output Line Prefix Control section of the grep manual page:

   -h, --no-filename
          Suppress the prefixing of file names on  output.   This  is  the
          default  when there is only one file (or only standard input) to
          search.