Introduction to Regular Expressions

If you do any kind of system admin on Linux or you are a programmer working with strings then you will likely have to use regular expressions, a way to define search patterns for string matching. Here is my introduction tutorial.

Licensed under Creative Commons: By Attribution 3.0 License

#garyexplains

[alliejr]

Excellent job Professor Sims! Also, O’Reilly published a book, “Regular Expression Pocket Reference” which I still use because the obtuse matching rules are quite difficult to memorize. I also suggest that programmers Google for common regex solutions rather than reinventing the wheel.

[nimrodlevy]

To whom ever start coding its a very very important lecture and its for free! And its a very very good one! Go and practice it. Especially if you want to code compilers, Sometimes its a life saver!

[RobertBartlettBaron]

You might have also pointed out that a little bit of theory, that is regular expressions can be implemented as a finite state machine (grep and egrep are commonly defined this way). Another thing to mention is that regular expressions are commonly used in the lexical analysis stage of compilers. This video was more of an introduction to grep than an introduction to the very broad topic of regular expressions.

[adamdmer]

Good job, Gary. Thanks for the short, sweet intro. to searching text with regular expressions.

[BernieD]

Gary, I've been a e\grep user for years and you showed me a few tricks I did not know. Thanks!

[marketqueue]

This is REGEX 101... thanks for making this video...

[RanggaWiratno]

I use this a lot for grep log files and sed some configuration files, really helped a lot in learning regex deeper

[mohamedsalman]

Great Explanation Professor, sending my greeting from San Francisco California.

[Chalisque]

One handy script I have, called filesrx, allows the use of python's regular expressions in batch renames. Basically 'filesrx <regex> <replacement> [...files]'.

[FaizanAnwerAli]

This is probably the only thing that I already knew and already using it in development

[randomgyandu]

Thank you sir ! For making video on this topic

[ganymedeshortride]

Grate stuff! Don't know what I grep so I found those useful videos. Thank you.

[sendgl]

Like the chest sheet mentioned at the end.

[frederik]

Very well explained. Thank you for the video.

[jkinder]

Learning quantitative vs qualitative for matching helps. To do more than just finding the pattern within a line, as much as I love python, I find perl best for quickly doing some pretty complex things with minimal coding.

[theJesai]

*Awesome video Garry! Keep up the good work* :)
_Like to show your love_

[filippoc.]

Eventually I watched it (coding is not for me). Thanks for the lesson and what a nice background Gary!

[MarkKeller]

*GARY!!!*
*Good Morning Professor!*
*Good Morning Fellow Classmates!*

[Xi_Pooh_Shill]

Regex is one of those basic stuff you need to know to be a developer. Sadly not everyone knows it.

[nelta]

Awesome tips sir. Very clear explanation thank you for the videos