Learning regular expressions
I have discovered Regular Expressions in LibreOffice (Search and Replace) and I have found it very useful. I have a few questions on RegEx. What is the best way to learn it? Is regex for libreoffice the same as in the grep command? Is regex in the grep-command the same as in the sed-command?
As you probably can guess from my questions, I don't have much experience with this, so be lenient please.