You're right, I'm using -r even when it's not necessary. To my defense I think it's a good habit to have since without it regex expressions are painful to write. I didn't considered that using -E it's a better choice but I'll correct that now. (one might argue again that typing -r is easier than -E :D ).

Regarding the definition of words - I also thought of that when I wrote that snippet. I know it's not the complete regex for a word and that word regex patterns might differ. And I was probably a bit lazy - but I'll correct it presently.

I'd also like to say that I didn't write this as an absolute and ultimate reference. If I'm honest I wrote this as much to teach others as to solidify this knowledge myself. Now since it seems it gained traction I'm kinda obligated to make this better, no? Darn. :)

PS: if you'd like to help me make this better please submit a pull request or leave a comment here. Looking at your profile I see that you try to limit your online time so I probably shouldn've asked. :P

Example "multiple replacements":

    #!/usr/bin/sed -f
    s/a/A/
    s/foo/BAR/
    s/hello/HELLO/

Also, FYI, this is the link for the POSIX specification for sed:

https://pubs.opengroup.org/onlinepubs/9699919799/utilities/s...

Notice that -i is not POSIX.

Example:

    sed '10{p;q;}' myfile.txt

PS: May I humbly point out that the command you provided will actually print up to line 10 and then a duplicate line. Like I said, unexpected (even though it seems logical). :)

This document shows practices of sed, but the author doesn't seem aware of best practices. A sed script starting with '#!/bin/bash' is a bad practice.

What other good practice suggestions do you have? (if you're comfortable answering and have the time)