Linux Commands Tutorial - Regular Expression basics

A tutorial on how to use Regular Expressions for egrep & sed to filter and modify text file content.

This tutorial covers commands like:
egrep, sed

Twitter: @lambdastartup

[Brejdaczki]

Just watched the whole video. Helped me a lot in preparations for an exam. Thanks!

[GoranObal]

Nice tutorial!
Couple of notes:
egrep does not need -E, only grep does. ;)
you can give sed more commands without the -e switch by delimiting them with a semicolon ;

[Brejdaczki]

Another thing I found that may have changed over the time is that:
Such syntax doesn't work anymore: sed 's/[0-9]/NOTE:\1/g' File
You can change that with: sed 's/[0-9]/NOTE:&/g' File
"&" being the Pattern you replace with sed. In this case numbers [0-9].

[rasmus]

Thank you very much for uploading. This was extremely enlightening.

[umersaeed]

I think its great content delivered with quite a bit of ease, thanks. Do upload more.

[nnd]

'^aa|bb$' is equal to '(^aa|bb$)' instead of '^a(a|b)b$'

[srinivaskulkarni]

I have a doubt.At 23:03 He says its combination of 'a' and 'b', but '[ab]' indicates either a or b .Then how come a line that has 'abab' got printed on screen.As there are neither 3 'a's nor 3 'b's .Please clear this as it has bugged my head :D

[jesusalfonso]

Thank you man, your explanation was very clear and help me understand it

[WarmShiningAir]

Guys, is there anyone who could help me to find the mistake?

Based on the information from the video i am trying to create a template to be able to see the lines like this:
Anna Hays 4, 5, 4, 3.5, 2, 5, 4, 5
My command here \\\ egrep -iE '[a-z]+\ [a-z]+\ (2|3|3\.5|4|4\.5|5|, )+$' /// does not work once as i add $ sign at the end.
However, if i delete this sign - the sense of filtering disappears as it is enough that numbers from the range only shows ones and should not last till the end.

The funniest thing is that even if i just filter lie this \\\ egrep -E '5$' /// line does not show up!

I would appreciate all the advices as i've tried all my assumptions. :)

[joshuahwang]

quick comment, don't sigh so much. you made me sleepy just listening to the vid. Good explanantion tho

[paxdriver]

I don't get why use egrep? You said it's for regular expressions but that is literally what the re in grep stand for; "global regular expression print"

[rajeevs]

should have taken better example :) little confusing

[saltyreese]

Bro, nice explanation but you need to teach a little faster