\nI mention back in my post from March 20, 2021<\/a> that on one system I use, grep handles the character classes \\d and \\w. Yet, one can’t count on all systems doing so.<\/p>\n Today I was using one in which grep wouldn’t work with \\d or \\w, but insisted on the character classes [[:digit:]], [[:alpha:]], [[:alnum:]], and so on. These are obviously not so convenient as Perl character classes (such as \\d and \\w); furthermore, [[:digit:]] is probably less convenient than [0-9]. \\d and \\w are big advantages of Perl regular expressions, which grep, by itself, isn’t expected to support.<\/p>\n I’ve read some people mention they use [:alpha:] and [:digit:] rather than the double-layer brackets. However, the double-layer brackets I find to be reliable, while [:digit:] or [:alpha:] only work sometimes. Such is my experience, anyway.<\/p>\n I’ll be posting more about grep, I expect:)<\/p>\n Source:<\/p>\n perldoc.perl.org<\/a><\/p>\n cyberciti.biz<\/a><\/p>\nJack of Oracle Tutoring by Jack and Diane,<\/a> Campbell River, BC.\n","protected":false},"excerpt":{"rendered":" Self-tutoring about computer science: the tutor continues about grep. I mention back in my post from March 20, 2021 that on one system I use, grep handles the character classes \\d and \\w. Yet, one can’t count on all systems …<\/p>\n