Pipe output to use as the search specification for grep on Linux

Question

How do I pipe the output of grep as the search pattern for another grep?

As an example:

grep   | xargs grep          


        

Answer 1

You should grep in such a way, to extract filenames only, see the parameter -l (the lowercase L):

grep -l someSearch * | xargs grep otherSearch

Because on the simple grep, the output is much more info than file names only. For instance when you do

grep someSearch *

You will pipe to xargs info like this

filename1: blablabla someSearch blablabla something else
filename2: bla someSearch bla otherSearch
...

Piping any of above line makes nonsense to pass to xargs. But when you do grep -l someSearch *, your output will look like this:

filename1
filename2

Such an output can be passed now to xargs