pwru VS pup

if you have a recent enough kernel, this change https://github.com/cilium/pwru/pull/148 means that it will print the reason the packet was dropped in the output - see https://lwn.net/Articles/885729/

There's a whole heap of reasons a packet can be dropped:

[pwru](https://github.com/cilium/pwru) is a fun new tool from the Cilium folks for tracing network packets in the kernel. Like tcpdump but it shows you the full path including kernel syscalls. Lets you debug much deeper than "when the packet gets to this port it gets dropped".

I recently came across another useful utility for debugging unexpected packet drops - PWRU[0] (Packet, Where Are You) by Cilium.

It uses eBPF to try to trace the path of the packet through the kernel. Haven't needed to use it yet, but it could have saved me a lot of trouble in the past.

[0]: https://github.com/cilium/pwru

And lnk=$(curl -s https://www.selfstudys.com$url |grep "PDFFlip" | cut -d '"' -f 6) to lnk=$(curl -s https://www.selfstudys.com$url | pup "div#PDFF attr{source}" ) here pup will print content of source attribute from div tag with id PDFF i dont know that much about html & css so this is what i came up with. but i am sure you can also select class & make list of suburls from them. check out the video from bugswriter on pup or read docs from git hub for more info github link: https://github.com/ericchiang/pup

jq is pretty amazing. If you are comfortable with its jquery-like CSS selector syntax, then I should also mention a couple similar cli utilities that apply it to HTML: htmlp and pup.

Regex is not a great tool for parsing web pages. Open up a browser dev tools window and select a bit of the page. Right click > copy... XPath expression or CSS selector. A proper web scraping tool will accept either of those. No muss, no fuss. You can even use simple command line tools: xpath or pup

This is HTML to JSON, written in Rust, and there's also pup[1] which I found out about just the other day on HN[2] which uses a very similar syntax (CSS selectors) but outputs HTML and is written in Go.

I can see room for both though it would interesting to have a more detailed comparison to go on (e.g. types of HTML, speed etc).

[1] https://github.com/ericchiang/pup

[2] https://news.ycombinator.com/item?id=33805732

It looks like the project became inactive for a bit and there are alternatives such as htmlq, etc. https://github.com/ericchiang/pup/issues/150

Another tool worth mentioning is pup - it can produce JSON output which means you can pipe it to jq