Two different approaches to debugging a software problem:

The Sudoku approach: stare at the limited set of clues you have, and think harder and harder about them until you find a way to deduce something useful.

The Minesweeper approach: don't even try to figure out the solution from only the clues you have right now. Instead, focus on finding a way to acquire another clue, and then using that to get another, and so on. Eventually you've collected so many clues that the answer is obvious.

Sometimes the Sudoku approach is necessary, because you've got all the clues you're ever going to get. But I think my new motto is "Never Sudoku a problem when you can Minesweeper it."

I was today years old when I learned that, in #Wireshark, you can define columns that source their values from multiple fields, for example:

tcp.dstport || udp.dstport

Suppose you're using less(1) to view a config file that has lots of commented-out explanations and defaults:

less /etc/ssh/ssh_config

It's hard to really see which lines are in effect and which are just comments, especially without syntax highlighting.

But! You can use less's filtering capabilities to only display lines that start with a character that's not a hash symbol. Type "&" and enter a regular expression, then hit return. For example:

&^[^#]

Enter an empty regex to stop filtering.

'mkdir -p' lets you make a deeply nested subdirectory like a/b/c/d, making all the intermediate directories on the way to it. So if even 'a' doesn't exist, it'll make that, then a/b, etc.

But you can also get it to make multiple _non_-nested directories, because it accepts '..' in the path and doesn't treat it specially:

$ mkdir -p alpha/../beta/../gamma
$ ls
alpha beta gamma
$

[Edit: to be clear, I'm pointing out an amusing edge case, not giving advice!]

I just published my second ever crate and first app ever, memlimit! https://lib.rs/crates/memlimit

it's always stressful to put forward something i made onto the public world, but here i go!

it's a process memory limiter: you invoke a command with it, and if it consumes more than the specified amount of memory, it kills the process it spawned. i think it could be useful in some niche cases, i.e. having a way to forcefully kill a rust program you're bisecting for a rustc bug

i was not aware of any program that did this, and after an extremely small amount of research, decided it would be fun to make a program that specifically only did this. enjoy, i guess!