Phpexec () a shell error occurs because grep in php can only process text streams, but binary streams cannot.

Failed | & nbsp; grep & nbsp; 'startup' & nbsp; | wc-l test in the linux command line. No problem occurs in a shell result of php exec, the reason is that grep in php can only process text streams, but binary streams cannot.
Cat aa.txt | grep 'startup' | wc-l is available in linux command lines. But the exec in php has a problem, which is strange. Result: the following error occurs: cat: write error: Broken pipe.

I spent a lot of effort, checked a lot of information, and finally solved the problem. -A option is added to the grep option.
The grep-a option indicates Process a binary file as if it were text; this is equivalent to the -- binary-files = text option

It should be cat. The file contains a binary stream, which causes grep to not recognize it.