_\bp_\ba_\bt_\bt_\be_\br_\bn. On systems with POSIX regular expression
support, the pattern may be an extended regular
expression. On systems without POSIX regular
_\bp_\ba_\bt_\bt_\be_\br_\bn. On systems with POSIX regular expression
support, the pattern may be an extended regular
expression. On systems without POSIX regular