That would have failed even if -[r|R] were supported. A line from procnamelist, which is a pattern to match, is treated as a filename argument to -f. If you put procnamelist where it belongs, after -f, the pipe and while loop serve no purpose.
Originally Posted by pamu
while read line
cat file | grep "$line"
The sole reason for the existence of this thread is file system traversal. This proposal is an infinite loop that reads one file over and over and over and ...