plan9-cat.1 %2Fhome%2Fmarcos%2FEvidencias%2FBulk_PC-20170427_%2Frfc822.txt %7C egrep %22%5B0-9%5D*%5B.%5D%2B%5B0-9%5D*%5B.%5D%5B0-9%5D*%5B.%5D%5B0-9%5D*%22 
catenate files
source manpages: plan9-cat