As I write this, Firefox 72 is the just released version of Firefoxand 73 is in beta, but my primary Firefox is still a custom hackedversion that I build from the development tree ,so it most closely corresponds to what will be released as Firefox74 in a certain amount of time (I've lost track of how fast Firefoxmakes releases). Since it's been about ten versions of Firefox (andmore than a year) since the last time I covered my addons ,

In response to my entry on my current Firefox addons , hwj asked a good question in the lobste.rs comments :

Isn’t uMatrix an advanced version of uBlock Origin? What’s therationale behind using both of them?

While it's true that uMatrix and uBlock Origin haveoverlapping functionality (and are written by the same person),they have different purposes and focuses. uBlock Origin's focus isblocking ads and other undesired things as an out of the boxexperience with little configuration needed. uMatrix

These days, it seems that a lot of people are talking about andpraising eBPF and tools like BCC and bpftrace , and you canread about places such as Facebook and Netflix routinely usingdozens of eBPF programs on systems in production. All of these aretrue, by and large; if you have the expertise and in the rightenvironment, eBPF can do great things. Unfortunately, though, anumber of things get in the way of more ordinary sysadmins beingable to use eBPF and these eBPF tools for powerful things

Suppose, not hypothetically, that you're a Unix person with somenumber of iOS devices, such as a phone and a tablet , and you wind up with files inone environment that you would like to move to or access from theother. On the iOS devices you may have photos and videos you wantto move to Unix to deal with them with familiar tools, and on Unixyou may have files that you edit or read or refer to and you'd liketo do that on your portable devices

Suppose that you have some scripts that you use to extract andgenerate Prometheus metrics for targets, and these scripts run onyour Prometheus server. These metrics might be detailed SNTP metricsof (remote) NTP servers, IMAP and POP3 login performance metrics,and so on. You have at least three methods to expose these scriptmetrics to Prometheus ; you can runthem from cron and publish through either node_exporter 's textfile collector or Pushgateway ,or you can use the third part script_exporter to run your

In our Prometheus environment , we'vewound up wanting (and creating) a bunch of custom metrics that aremost naturally created through a variety of scripts. Some of theseare general things that are simply not implemented to our tastesin existing scripts and exporters, such as SMART disk metrics, andsome of these are completely custom metrics for our environment,such as our per-user, per-filesystem disk space usage information or information from our machine roomtemperature sensors (which come from an assortment of vendors and

On modern versions of Unix, the SIGCHLD signal is sent to a processwhen one of its child processes terminates or some other statuschanges happen. Catching SIGCHLD is a handy way to find out aboutchild processes exiting while your program is doing other things,and ignoring it will make them vanish instead of turning intozombies. Despite all of these useful things, SIGCHLD was not inV7 Unix; it was added in 4.2 BSD and independently in System III(as SIGCLD ).

In V7, programs

I said recently in passing that errno was a generally goodinterface in pre-threading Unix . That mayraise some eyebrows, so today let's talk about the good and thebad parts of errno in a traditional Unix environment, such asV7 Unix.

The good part of errno is that it's about the simplest thing that canwork to provide multiple values from system calls in C, which doesn'tdirectly have multi-value returns (especially in early C). Using aglobal variable to

In light of my switch to basing my GNU Emacs Go environment onlsp-mode , I decided to revisit a bunch of .emacs stuff that I was previously using and take out things thatseemed outdated or that I wasn't using any more. In general, mycurrent assumption is that Go's big switch to using modules willprobably break any tool for dealing with Go code that hasn't beenupdated, so all of them are suspect until proven otherwise. For myown reasons, I want to