I would like to get some explanations about regular expressions. For example if we have expression like this /[Blb]it$/ what would be match for this regular expression i mean words that would match this expression and if an expert can give me little explanation.
Also if for example I want to find out the expression that would match firstname.lastname@example.org what expression I would need to use
Also I would like to get explanation for example if I am copying something
for example if i go to cd /home/test directory and I copy content of a folder like cp -rfp /home/new/* . what the asterisk and dot mean at the end of syntax