sed -i -E "s/еж([аиу][^а-я])/ёжик\1/g" *ru*
grep -E "еж[аиу][^а-я]" *ru*
Comment: [^а-я] includes all spaces and punctuation and also finish of string
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>get-task-allow</key>
<false/>
</dict>
</plist>