# echo á | grep '[[=a=]]'# echo ô | grep '[[=o=]]'# On Linux to compare: # echo á | grep '[[=a=]]'á# echo ô | grep '[[=o=]]'ô# «STANDARDSThe grep utility is compliant with the IEEE Std 1003.1-2008 (“POSIX.1”) specification». http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man1/egrep.1?query=grep
IEEE Std 1003.1: «9.3.5 RE Bracket Expression...It consists of one or more expressions: collating elements, collating symbols, equivalence classes...» http://pubs.opengroup.org/onlinepubs/009696899/basedefs/xbd_chap09.html
