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Hello! Today I want to talk about ANSI escape codes. For a long time I was vaguely aware of ANSI escape codes (“that’s how you make text red in the terminal and stuff”) but I had no real understanding of where they were supposed to be defined or whether or not there were standards for them. I just had a kind of vague “there be dragons” feeling around them. While learning about the terminal this year, I’ve learned that: ANSI escape codes are responsible for a lot of usability improvements in the terminal (did you know there’s a way to copy to your system clipboard when SSHed into a remote machine?? It’s an escape code called OSC 52!) They aren’t completely standardized, and because of that they don’t always work reliably. And because they’re also invisible, it’s extremely frustrating to troubleshoot escape code issues. So I wanted to put together a list for myself of some standards that exist around escape codes, because I want to know if they have to feel unreliable and frustrating, or...
3 weeks ago

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More from Julia Evans

How to add a directory to your PATH

I was talking to a friend about how to add a directory to your PATH today. It’s something that feels “obvious” to me since I’ve been using the terminal for a long time, but when I searched for instructions for how to do it, I actually couldn’t find something that explained all of the steps – a lot of them just said “add this to ~/.bashrc”, but what if you’re not using bash? What if your bash config is actually in a different file? And how are you supposed to figure out which directory to add anyway? So I wanted to try to write down some more complete directions and mention some of the gotchas I’ve run into over the years. Here’s a table of contents: step 1: what shell are you using? step 2: find your shell’s config file a note on bash’s config file step 3: figure out which directory to add step 3.1: double check it’s the right directory step 4: edit your shell config step 5: restart your shell problems: problem 1: it ran the wrong program problem 2: the program isn’t being run from your shell notes: a note on source a note on fish_add_path step 1: what shell are you using? If you’re not sure what shell you’re using, here’s a way to find out. Run this: ps -p $$ -o pid,comm= if you’re using bash, it’ll print out 97295 bash if you’re using zsh, it’ll print out 97295 zsh if you’re using fish, it’ll print out an error like “In fish, please use $fish_pid” ($$ isn’t valid syntax in fish, but in any case the error message tells you that you’re using fish, which you probably already knew) Also bash is the default on Linux and zsh is the default on Mac OS (as of 2024). I’ll only cover bash, zsh, and fish in these directions. step 2: find your shell’s config file in zsh, it’s probably ~/.zshrc in bash, it might be ~/.bashrc, but it’s complicated, see the note in the next section in fish, it’s probably ~/.config/fish/config.fish (you can run echo $__fish_config_dir if you want to be 100% sure) a note on bash’s config file Bash has three possible config files: ~/.bashrc, ~/.bash_profile, and ~/.profile. If you’re not sure which one your system is set up to use, I’d recommend testing this way: add echo hi there to your ~/.bashrc Restart your terminal If you see “hi there”, that means ~/.bashrc is being used! Hooray! Otherwise remove it and try the same thing with ~/.bash_profile You can also try ~/.profile if the first two options don’t work. (there are a lot of elaborate flow charts out there that explain how bash decides which config file to use but IMO it’s not worth it and just testing is the fastest way to be sure) step 3: figure out which directory to add Let’s say that you’re trying to install and run a program called http-server and it doesn’t work, like this: $ npm install -g http-server $ http-server bash: http-server: command not found How do you find what directory http-server is in? Honestly in general this is not that easy – often the answer is something like “it depends on how npm is configured”. A few ideas: Often when setting up a new installer (like cargo, npm, homebrew, etc), when you first set it up it’ll print out some directions about how to update your PATH. So if you’re paying attention you can get the directions then. Sometimes installers will automatically update your shell’s config file to update your PATH for you Sometimes just Googling “where does npm install things?” will turn up the answer Some tools have a subcommand that tells you where they’re configured to install things, like: Homebrew: brew --prefix (and then append /bin/ and /sbin/ to what that gives you) Node/npm: npm config get prefix (then append /bin/) Go: go env | grep GOPATH (then append /bin/) asdf: asdf info | grep ASDF_DIR (then append /bin/ and /shims/) step 3.1: double check it’s the right directory Once you’ve found a directory you think might be the right one, make sure it’s actually correct! For example, I found out that on my machine, http-server is in ~/.npm-global/bin. I can make sure that it’s the right directory by trying to run the program http-server in that directory like this: $ ~/.npm-global/bin/http-server Starting up http-server, serving ./public It worked! Now that you know what directory you need to add to your PATH, let’s move to the next step! step 4: edit your shell config Now we have the 2 critical pieces of information we need: Which directory you’re trying to add to your PATH (like ~/.npm-global/bin/) Where your shell’s config is (like ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish) Now what you need to add depends on your shell: bash and zsh instructions: Open your shell’s config file, and add a line like this: export PATH=$PATH:~/.npm-global/bin/ (obviously replace ~/.npm-global/bin with the actual directory you’re trying to add) fish instructions: In fish, the syntax is different: set PATH $PATH ~/.npm-global/bin (in fish you can also use fish_add_path, some notes on that further down) step 5: restart your shell Now, an extremely important step: updating your shell’s config won’t take effect if you don’t restart it! Two ways to do this: open a new terminal (or terminal tab), and maybe close the old one so you don’t get confused Run bash to start a new shell (or zsh if you’re using zsh, or fish if you’re using fish) I’ve found that both of these usually work fine. And you should be done! Try running the program you were trying to run and hopefully it works now. If not, here are a couple of problems that you might run into: problem 1: it ran the wrong program If the wrong version of a is program running, you might need to add the directory to the beginning of your PATH instead of the end. For example, on my system I have two versions of python3 installed, which I can see by running which -a: $ which -a python3 /usr/bin/python3 /opt/homebrew/bin/python3 The one your shell will use is the first one listed. If you want to use the Homebrew version, you need to add that directory (/opt/homebrew/bin) to the beginning of your PATH instead, by putting this in your shell’s config file (it’s /opt/homebrew/bin/:$PATH instead of the usual $PATH:/opt/homebrew/bin/) export PATH=/opt/homebrew/bin/:$PATH or in fish: set PATH ~/.cargo/bin $PATH problem 2: the program isn’t being run from your shell All of these directions only work if you’re running the program from your shell. If you’re running the program from an IDE, from a GUI, in a cron job, or some other way, you’ll need to add the directory to your PATH in a different way, and the exact details might depend on the situation. in a cron job Some options: use the full path to the program you’re running, like /home/bork/bin/my-program put the full PATH you want as the first line of your crontab (something like PATH=/bin:/usr/bin:/usr/local/bin:….). You can get the full PATH you’re using in your shell by running echo "PATH=$PATH". I’m honestly not sure how to handle it in an IDE/GUI because I haven’t run into that in a long time, will add directions here if someone points me in the right direction. a note on source When you install cargo (Rust’s installer) for the first time, it gives you these instructions for how to set up your PATH, which don’t mention a specific directory at all. This is usually done by running one of the following (note the leading DOT): . "$HOME/.cargo/env" # For sh/bash/zsh/ash/dash/pdksh source "$HOME/.cargo/env.fish" # For fish The idea is that you add that line to your shell’s config, and their script automatically sets up your PATH (and potentially other things) for you. This is pretty common (Homebrew and asdf have something similar), and there are two ways to approach this: Just do what the tool suggests (add . "$HOME/.cargo/env" to your shell’s config) Figure out which directories the script they’re telling you to run would add to your PATH, and then add those manually. Here’s how I’d do that: Run . "$HOME/.cargo/env" in my shell (or the fish version if using fish) Run echo "$PATH" | tr ':' '\n' | grep cargo to figure out which directories it added See that it says /Users/bork/.cargo/bin and shorten that to ~/.cargo/bin Add the directory ~/.cargo/bin to PATH (with the directions in this post) I don’t think there’s anything wrong with doing what the tool suggests (it might be the “best way”!), but personally I usually use the second approach because I prefer knowing exactly what configuration I’m changing. a note on fish_add_path fish has a handy function called fish_add_path that you can run to add a directory to your PATH like this: fish_add_path /some/directory This will add the directory to your PATH, and automatically update all running fish shells with the new PATH. You don’t have to update your config at all! This is EXTREMELY convenient, but one downside (and the reason I’ve personally stopped using it) is that if you ever need to remove the directory from your PATH a few weeks or months later because maybe you made a mistake, it’s kind of hard to do (there are instructions in this comments of this github issue though). that’s all Hopefully this will help some people. Let me know (on Mastodon or Bluesky) if you there are other major gotchas that have tripped you up when adding a directory to your PATH, or if you have questions about this post!

a month ago 18 votes
Some terminal frustrations

A few weeks ago I ran a terminal survey (you can read the results here) and at the end I asked: What’s the most frustrating thing about using the terminal for you? 1600 people answered, and I decided to spend a few days categorizing all the responses. Along the way I learned that classifying qualitative data is not easy but I gave it my best shot. I ended up building a custom tool to make it faster to categorize everything. As with all of my surveys the methodology isn’t particularly scientific. I just posted the survey to Mastodon and Twitter, ran it for a couple of days, and got answers from whoever happened to see it and felt like responding. Here are the top categories of frustrations! I think it’s worth keeping in mind while reading these comments that 40% of people answering this survey have been using the terminal for 21+ years 95% of people answering the survey have been using the terminal for at least 4 years These comments aren’t coming from total beginners. Here are the categories of frustrations! The number in brackets is the number of people with that frustration. Honestly I don’t how how interesting this is to other people – I’m just writing this up for myself because I’m trying to write a zine about the terminal and I wanted to get a sense for what people are having trouble with. remembering syntax (115) People talked about struggles remembering: the syntax for CLI tools like awk, jq, sed, etc the syntax for redirects keyboard shortcuts for tmux, text editing, etc One example comment: There are just so many little “trivia” details to remember for full functionality. Even after all these years I’ll sometimes forget where it’s 2 or 1 for stderr, or forget which is which for > and >>. switching terminals is hard (91) People talked about struggling with switching systems (for example home/work computer or when SSHing) and running into: OS differences in keyboard shortcuts (like Linux vs Mac) systems which don’t have their preferred text editor (“no vim” or “only vim”) different versions of the same command (like Mac OS grep vs GNU grep) no tab completion a shell they aren’t used to (“the subtle differences between zsh and bash”) as well as differences inside the same system like pagers being not consistent with each other (git diff pagers, other pagers). One example comment: I got used to fish and vi mode which are not available when I ssh into servers, containers. color (85) Lots of problems with color, like: programs setting colors that are unreadable with a light background color finding a colorscheme they like (and getting it to work consistently across different apps) color not working inside several layers of SSH/tmux/etc not liking the defaults not wanting color at all and struggling to turn it off This comment felt relatable to me: Getting my terminal theme configured in a reasonable way between the terminal emulator and fish (I did this years ago and remember it being tedious and fiddly and now feel like I’m locked into my current theme because it works and I dread touching any of that configuration ever again). keyboard shortcuts (84) Half of the comments on keyboard shortcuts were about how on Linux/Windows, the keyboard shortcut to copy/paste in the terminal is different from in the rest of the OS. Some other issues with keyboard shortcuts other than copy/paste: using Ctrl-W in a browser-based terminal and closing the window the terminal only supports a limited set of keyboard shortcuts (no Ctrl-Shift-, no Super, no Hyper, lots of ctrl- shortcuts aren’t possible like Ctrl-,) the OS stopping you from using a terminal keyboard shortcut (like by default Mac OS uses Ctrl+left arrow for something else) issues using emacs in the terminal backspace not working (2) other copy and paste issues (75) Aside from “the keyboard shortcut for copy and paste is different”, there were a lot of OTHER issues with copy and paste, like: copying over SSH how tmux and the terminal emulator both do copy/paste in different ways dealing with many different clipboards (system clipboard, vim clipboard, the “middle click” keyboard on Linux, tmux’s clipboard, etc) and potentially synchronizing them random spaces added when copying from the terminal pasting multiline commands which automatically get run in a terrifying way wanting a way to copy text without using the mouse discoverability (55) There were lots of comments about this, which all came down to the same basic complaint – it’s hard to discover useful tools or features! This comment kind of summed it all up: How difficult it is to learn independently. Most of what I know is an assorted collection of stuff I’ve been told by random people over the years. steep learning curve (44) A lot of comments about it generally having a steep learning curve. A couple of example comments: After 15 years of using it, I’m not much faster than using it than I was 5 or maybe even 10 years ago. and That I know I could make my life easier by learning more about the shortcuts and commands and configuring the terminal but I don’t spend the time because it feels overwhelming. history (42) Some issues with shell history: history not being shared between terminal tabs (16) limits that are too short (4) history not being restored when terminal tabs are restored losing history because the terminal crashed not knowing how to search history One example comment: It wasted a lot of time until I figured it out and still annoys me that “history” on zsh has such a small buffer; I have to type “history 0” to get any useful length of history. bad documentation (37) People talked about: documentation being generally opaque lack of examples in man pages programs which don’t have man pages Here’s a representative comment: Finding good examples and docs. Man pages often not enough, have to wade through stack overflow scrollback (36) A few issues with scrollback: programs printing out too much data making you lose scrollback history resizing the terminal messes up the scrollback lack of timestamps GUI programs that you start in the background printing stuff out that gets in the way of other programs’ outputs One example comment: When resizing the terminal (in particular: making it narrower) leads to broken rewrapping of the scrollback content because the commands formatted their output based on the terminal window width. “it feels outdated” (33) Lots of comments about how the terminal feels hampered by legacy decisions and how users often end up needing to learn implementation details that feel very esoteric. One example comment: Most of the legacy cruft, it would be great to have a green field implementation of the CLI interface. shell scripting (32) Lots of complaints about POSIX shell scripting. There’s a general feeling that shell scripting is difficult but also that switching to a different less standard scripting language (fish, nushell, etc) brings its own problems. Shell scripting. My tolerance to ditch a shell script and go to a scripting language is pretty low. It’s just too messy and powerful. Screwing up can be costly so I don’t even bother. more issues Some more issues that were mentioned at least 10 times: (31) inconsistent command line arguments: is it -h or help or –help? (24) keeping dotfiles in sync across different systems (23) performance (e.g. “my shell takes too long to start”) (20) window management (potentially with some combination of tmux tabs, terminal tabs, and multiple terminal windows. Where did that shell session go?) (17) generally feeling scared/uneasy (“The debilitating fear that I’m going to do some mysterious Bad Thing with a command and I will have absolutely no idea how to fix or undo it or even really figure out what happened”) (16) terminfo issues (“Having to learn about terminfo if/when I try a new terminal emulator and ssh elsewhere.”) (16) lack of image support (sixel etc) (15) SSH issues (like having to start over when you lose the SSH connection) (15) various tmux/screen issues (for example lack of integration between tmux and the terminal emulator) (15) typos & slow typing (13) the terminal getting messed up for various reasons (pressing Ctrl-S, cating a binary, etc) that’s all! I’m not going to make a lot of commentary on these results, but here are a couple of categories that feel related to me: remembering syntax & history (often the thing you need to remember is something you’ve run before!) discoverability & the learning curve (the lack of discoverability is definitely a big part of what makes it hard to learn)

a month ago 20 votes
What's involved in getting a "modern" terminal setup?

Hello! Recently I ran a terminal survey and I asked people what frustrated them. One person commented: There are so many pieces to having a modern terminal experience. I wish it all came out of the box. My immediate reaction was “oh, getting a modern terminal experience isn’t that hard, you just need to….”, but the more I thought about it, the longer the “you just need to…” list got, and I kept thinking about more and more caveats. So I thought I would write down some notes about what it means to me personally to have a “modern” terminal experience and what I think can make it hard for people to get there. what is a “modern terminal experience”? Here are a few things that are important to me, with which part of the system is responsible for them: multiline support for copy and paste: if you paste 3 commands in your shell, it should not immediatly run them all! That’s scary! (shell, terminal emulator) infinite shell history: if I run a command in my shell, it should be saved forever, not deleted after 500 history entries or whatever. Also I want commands to be saved to the history immediately when I run them, not only when I exit the shell session (shell) a useful prompt: I can’t live without having my current directory and current git branch in my prompt (shell) 24-bit colour: this is important to me because I find it MUCH easier to theme neovim with 24-bit colour support than in a terminal with only 256 colours (terminal emulator) clipboard integration between vim and my operating system so that when I copy in Firefox, I can just press p in vim to paste (text editor, maybe the OS/terminal emulator too) good autocomplete: for example commands like git should have command-specific autocomplete (shell) having colours in ls (shell config) a terminal theme I like: I spend a lot of time in my terminal, I want it to look nice and I want its theme to match my terminal editor’s theme. (terminal emulator, text editor) automatic terminal fixing: If a programs prints out some weird escape codes that mess up my terminal, I want that to automatically get reset so that my terminal doesn’t get messed up (shell) keybindings: I want Ctrl+left arrow to work (shell or application) being able to use the scroll wheel in programs like less: (terminal emulator and applications) There are a million other terminal conveniences out there and different people value different things, but those are the ones that I would be really unhappy without. how I achieve a “modern experience” My basic approach is: use the fish shell. Mostly don’t configure it, except to: set the EDITOR environment variable to my favourite terminal editor alias ls to ls --color=auto use any terminal emulator with 24-bit colour support. In the past I’ve used GNOME Terminal, Terminator, and iTerm, but I’m not picky about this. I don’t really configure it other than to choose a font. use neovim, with a configuration that I’ve been very slowly building over the last 9 years or so (the last time I deleted my vim config and started from scratch was 9 years ago) use the base16 framework to theme everything some “out of the box” options for a “modern” experience What if you want a nice experience, but don’t want to spend a lot of time on configuration? Figuring out how to configure vim in a way that I was satisfied with really did take me like ten years, which is a long time! My best ideas for how to get a reasonable terminal experience with minimal config are: shell: either fish or zsh with oh-my-zsh terminal emulator: almost anything with 24-bit colour support, for example all of these are popular: linux: GNOME Terminal, Konsole, Terminator, xfce4-terminal mac: iTerm (Terminal.app doesn’t have 256-colour support) cross-platform: kitty, alacritty, wezterm, or ghostty shell config: set the EDITOR environment variable to your favourite terminal text editor maybe alias ls to ls --color=auto text editor: this is a tough one, maybe micro or helix? I haven’t used either of them seriously but they both seem like very cool projects and I think it’s amazing that you can just use all the usual GUI editor commands (Ctrl-C to copy, Ctrl-V to paste, Ctrl-A to select all) in micro and they do what you’d expect. I would probably try switching to helix except that retraining my vim muscle memory seems way too hard and I have a working vim config already. Personally I wouldn’t use xterm, rxvt, or Terminal.app as a terminal emulator, because I’ve found in the past that they’re missing core features (like 24-bit colour in Terminal.app’s case) that make the terminal harder to use for me. I don’t want to pretend that getting a “modern” terminal experience is easier than it is though – I think there are two issues that make it hard. Let’s talk about them! issue 1 with getting to a “modern” experience: the shell bash and zsh are by far the two most popular shells, and neither of them provide a default experience that I would be happy using out of the box, for example: you need to customize your prompt they don’t come with git completions by default, you have to set them up by default, bash only stores 500 (!) lines of history and (at least on Mac OS) zsh is only configured to store 2000 lines, which is still not a lot I find bash’s tab completion very frustrating, if there’s more than one match then you can’t tab through them And even though I love fish, the fact that it isn’t POSIX does make it hard for a lot of folks to make the switch. Of course it’s totally possible to learn how to customize your prompt in bash or whatever, and it doesn’t even need to be that complicated (in bash I’d probably start with something like export PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ ', or maybe use starship). But each of these “not complicated” things really does add up and it’s especially tough if you need to keep your config in sync across several systems. An extremely popular solution to getting a “modern” shell experience is oh-my-zsh. It seems like a great project and I know a lot of people use it very happily, but I’ve struggled with configuration systems like that in the past – it looks like right now the base oh-my-zsh adds about 3000 lines of config, and often I find that having an extra configuration system makes it harder to debug what’s happening when things go wrong. I personally have a tendency to use the system to add a lot of extra plugins, make my system slow, get frustrated that it’s slow, and then delete it completely and write a new config from scratch. issue 2 with getting to a “modern” experience: the text editor In the terminal survey I ran recently, the most popular terminal text editors by far were vim, emacs, and nano. I think the main options for terminal text editors are: use vim or emacs and configure it to your liking, you can probably have any feature you want if you put in the work use nano and accept that you’re going to have a pretty limited experience (for example as far as I can tell if you want to copy some text from nano and put it in your system clipboard you just… can’t?) use micro or helix which seem to offer a pretty good out-of-the-box experience, potentially occasionally run into issues with using a less mainstream text editor just avoid using a terminal text editor as much as possible, maybe use VSCode, use VSCode’s terminal for all your terminal needs, and mostly never edit files in the terminal issue 3: individual applications The last issue is that sometimes individual programs that I use are kind of annoying. For example on my Mac OS machine, /usr/bin/sqlite3 doesn’t support the Ctrl+Left Arrow keyboard shortcut. Fixing this to get a reasonable terminal experience in SQLite was a little complicated, I had to: realize why this is happening (Mac OS won’t ship GNU tools, and “Ctrl-Left arrow” support comes from GNU readline) find a workaround (install sqlite from homebrew, which does have readline support) adjust my environment (put Homebrew’s sqlite3 in my PATH) I find that debugging application-specific issues like this is really not easy and often it doesn’t feel “worth it” – often I’ll end up just dealing with various minor inconveniences because I don’t want to spend hours investigating them. The only reason I was even able to figure this one out at all is that I’ve been spending a huge amount of time thinking about the terminal recently. A big part of having a “modern” experience using terminal programs is just using newer terminal programs, for example I can’t be bothered to learn a keyboard shortcut to sort the columns in top, but in htop I can just click on a column heading with my mouse to sort it. So I use htop instead! But discovering new more “modern” command line tools isn’t easy (though I made a list here), finding ones that I actually like using in practice takes time, and if you’re SSHed into another machine, they won’t always be there. everything affects everything else Something I find tricky about configuring my terminal to make everything “nice” is that changing one seemingly small thing about my workflow can really affect everything else. For example right now I don’t use tmux. But if I needed to use tmux again (for example because I was doing a lot of work SSHed into another machine), I’d need to think about a few things, like: if I wanted tmux’s copy to synchronize with my system clipboard over SSH, I’d need to make sure that my terminal emulator has OSC 52 support if I wanted to use iTerm’s tmux integration (which makes tmux tabs into iTerm tabs), I’d need to change how I configure colours – right now I set them with a shell script that I run when my shell starts, but that means the colours get lost when restoring a tmux session. and probably more things I haven’t thought of. “Using tmux means that I have to change how I manage my colours” sounds unlikely, but that really did happen to me and I decided “well, I don’t want to change how I manage colours right now, so I guess I’m not using that feature!”. It’s also hard to remember which features I’m relying on – for example maybe my current terminal does have OSC 52 support and because copying from tmux over SSH has always Just Worked I don’t even realize that that’s something I need, and then it mysteriously stops working when I switch terminals. change things slowly Personally even though I think my setup is not that complicated, it’s taken me 20 years to get to this point! Because terminal config changes are so likely to have unexpected and hard-to-understand consequences, I’ve found that if I change a lot of terminal configuration all at once it makes it much harder to understand what went wrong if there’s a problem, which can be really disorienting. So I prefer to make pretty small changes, and accept that changes can might take me a REALLY long time to get used to. For example I switched from using ls to eza a year or two ago and while I think I like it I’m still not quite sure about it. getting a “modern” terminal is not that easy Trying to explain how “easy” it is to configure your terminal really just made me think that it’s kind of hard and that I still sometimes get confused. I’ve found that there’s never one perfect way to configure things in the terminal that will be compatible with every single other thing. I just need to try stuff, figure out some kind of locally stable state that works for me, and accept that if I start using a new tool it might disrupt the system and I might need to rethink things.

2 months ago 50 votes
"Rules" that terminal programs follow

Recently I’ve been thinking about how everything that happens in the terminal is some combination of: Your operating system’s job Your shell’s job Your terminal emulator’s job The job of whatever program you happen to be running (like top or vim or cat) The first three (your operating system, shell, and terminal emulator) are all kind of known quantities – if you’re using bash in GNOME Terminal on Linux, you can more or less reason about how how all of those things interact, and some of their behaviour is standardized by POSIX. But the fourth one (“whatever program you happen to be running”) feels like it could do ANYTHING. How are you supposed to know how a program is going to behave? This post is kind of long so here’s a quick table of contents: programs behave surprisingly consistently these are meant to be descriptive, not prescriptive it’s not always obvious which “rules” are the program’s responsibility to implement rule 1: noninteractive programs should quit when you press Ctrl-C rule 2: TUIs should quit when you press q rule 3: REPLs should quit when you press Ctrl-D on an empty line rule 4: don’t use more than 16 colours rule 5: vaguely support readline keybindings rule 5.1: Ctrl-W should delete the last word rule 6: disable colours when writing to a pipe rule 7: - means stdin/stdout these “rules” take a long time to learn programs behave surprisingly consistently As far as I know, there are no real standards for how programs in the terminal should behave – the closest things I know of are: POSIX, which mostly dictates how your terminal emulator / OS / shell should work together. It does specify a few things about how core utilities like cp should work but AFAIK it doesn’t have anything to say about how for example htop should behave. these command line interface guidelines But even though there are no standards, in my experience programs in the terminal behave in a pretty consistent way. So I wanted to write down a list of “rules” that in my experience programs mostly follow. these are meant to be descriptive, not prescriptive My goal here isn’t to convince authors of terminal programs that they should follow any of these rules. There are lots of exceptions to these and often there’s a good reason for those exceptions. But it’s very useful for me to know what behaviour to expect from a random new terminal program that I’m using. Instead of “uh, programs could do literally anything”, it’s “ok, here are the basic rules I expect, and then I can keep a short mental list of exceptions”. So I’m just writing down what I’ve observed about how programs behave in my 20 years of using the terminal, why I think they behave that way, and some examples of cases where that rule is “broken”. it’s not always obvious which “rules” are the program’s responsibility to implement There are a bunch of common conventions that I think are pretty clearly the program’s responsibility to implement, like: config files should go in ~/.BLAHrc or ~/.config/BLAH/FILE or /etc/BLAH/ or something --help should print help text programs should print “regular” output to stdout and errors to stderr But in this post I’m going to focus on things that it’s not 100% obvious are the program’s responsibility. For example it feels to me like a “law of nature” that pressing Ctrl-D should quit a REPL (“rule 3” below), but there’s no reason that that has to be always be true. The reason that Ctrl-D almost always works is that interactive REPLs almost all implement that keyboard shortcut. rule 1: noninteractive programs should quit when you press Ctrl-C The main reason for this rule is that noninteractive programs will quit by default on Ctrl-C if they don’t set up a SIGINT signal handler, so this is kind of a “you should act like the default” rule. Something that trips a lot of people up is that this doesn’t apply to interactive programs like python3 or bc or less. This is because in an interactive program, Ctrl-C has a different job – if the program is running an operation (like for example a search in less or some Python code in python3), then Ctrl-C will interrupt that operation but not stop the program. As an example of how this works in an interactive program: here’s the code in prompt-toolkit (the library that iPython uses for handling input) that aborts a search when you press Ctrl-C. rule 2: TUIs should quit when you press q TUI programs (like less or htop) will usually quit when you press q. This rule doesn’t apply to any program where pressing q to quit wouldn’t make sense, like tmux or text editors. rule 3: REPLs should quit when you press Ctrl-D on an empty line REPLs (like python3 or ed) will usually quit when you press Ctrl-D on an empty line. This rule is similar to the Ctrl-C rule – the reason for this is that by default if you’re running a program (like cat) in “cooked mode”, then the operating system will return an EOF when you press Ctrl-D on an empty line. Most of the REPLs I use (sqlite3, python3, fish, bash, etc) don’t actually use cooked mode, but they all implement this keyboard shortcut anyway to mimic the default behaviour. For example, here’s the code in prompt-toolkit that quits when you press Ctrl-D, and here’s the same code in readline. I actually thought that this one was a “Law of Terminal Physics” until very recently because I’ve basically never seen it broken, but you can see that it’s just something that each individual input library has to implement in the links above. Someone pointed out that the Erlang REPL does not quit when you press Ctrl-D, so I guess not every REPL follows this “rule”. rule 4: don’t use more than 16 colours Terminal programs rarely use colours other than the base 16 ANSI colours. This is because if you specify colours with a hex code, it’s very likely to clash with some users’ background colour. For example if I print out some text as #EEEEEE, it would be almost invisible on a white background, though it would look fine on a dark background. But if you stick to the default 16 base colours, you have a much better chance that the user has configured those colours in their terminal emulator so that they work reasonably well with their background color. Another reason to stick to the default base 16 colours is that it makes less assumptions about what colours the terminal emulator supports. The only programs I usually see breaking this “rule” are text editors, for example Helix by default will use a custom colorscheme with this very nice purple background which is not a default ANSI colour. It seems fine for Helix to break this rule since Helix isn’t a “core” program and I assume any Helix user who doesn’t like that colorscheme will just change the theme. rule 5: vaguely support readline keybindings Almost every program I use supports readline keybindings if it would make sense to do so. For example, here are a bunch of different programs and a link to where they define Ctrl-E to go to the end of the line: ipython (Ctrl-E defined here) atuin (Ctrl-E defined here) fzf (Ctrl-E defined here) zsh (Ctrl-E defined here) fish (Ctrl-E defined here) tmux’s command prompt (Ctrl-E defined here) None of those programs actually uses readline directly, they just sort of mimic emacs/readline keybindings. They don’t always mimic them exactly: for example atuin seems to use Ctrl-A as a prefix, so Ctrl-A doesn’t go to the beginning of the line. The exceptions to this are: some programs (like git, cat, and nc) don’t have any line editing support at all (except for backspace, Ctrl-W, and Ctrl-U) as usual text editors are an exception, every text editor has its own approach to editing text I wrote more about this “what keybindings does a program support?” question in entering text in the terminal is complicated. rule 5.1: Ctrl-W should delete the last word I’ve never seen a program (other than a text editor) where Ctrl-W doesn’t delete the last word. This is similar to the Ctrl-C rule – by default if a program is in “cooked mode”, the OS will delete the last word if you press Ctrl-W, and delete the whole line if you press Ctrl-U. So usually programs will imitate that behaviour. I can’t think of any exceptions to this other than text editors but if there are I’d love to hear about them! rule 6: disable colours when writing to a pipe Most programs will disable colours when writing to a pipe. For example: rg blah will highlight all occurrences of blah in the output, but if the output is to a pipe or a file, it’ll turn off the highlighting. ls --color=auto will use colour when writing to a terminal, but not when writing to a pipe Both of those programs will also format their output differently when writing to the terminal: ls will organize files into columns, and ripgrep will group matches with headings. If you want to force the program to use colour (for example because you want to look at the colour), you can use unbuffer to force the program’s output to be a tty like this: unbuffer rg blah | less -R I’m sure that there are some programs that “break” this rule but I can’t think of any examples right now. Some programs have an --color flag that you can use to force colour to be on. rule 7: - means stdin/stdout Usually if you pass - to a program instead of a filename, it’ll read from stdin or write to stdout (whichever is appropriate). For example, if you want to format the Python code that’s on your clipboard with black and then copy it, you could run: pbpaste | black - | pbcopy (pbpaste is a Mac program, you can do something similar on Linux with xclip) My impression is that most programs implement this if it would make sense and I can’t think of any exceptions right now, but I’m sure there are many exceptions. these “rules” take a long time to learn These rules took me a long time for me to learn because I had to: learn that the rule applied anywhere at all ("Ctrl-C will exit programs") notice some exceptions (“okay, Ctrl-C will exit find but not less”) subconsciously figure out what the pattern is ("Ctrl-C will generally quit noninteractive programs, but in interactive programs it might interrupt the current operation instead of quitting the program") eventually maybe formulate it into an explicit rule that I know A lot of my understanding of the terminal is honestly still in the “subconscious pattern recognition” stage. The only reason I’ve been taking the time to make things explicit at all is because I’ve been trying to explain how it works to others. Hopefully writing down these “rules” explicitly will make learning some of this stuff a little bit faster for others.

3 months ago 67 votes

More in programming

syntax highlighting with tree-sitter

I have added syntax highlighting to my blog using tree-sitter. Here are some notes about what I learned, with some complaining. static site generator markdown ingestion highlighting incompatible?! highlight names class names styling code results future work frontmatter templates feed style highlight quality static site generator I moved my blog to my own web site a few years ago. It is produced using a scruffy Rust program that converts a bunch of Markdown files to HTML using pulldown-cmark, and produces complete pages from Handlebars templates. Why did I write another static site generator? Well, partly as an exercise when learning Rust. Partly, since I wrote my own page templates, I’m not going to benefit from a library of existing templates. On the contrary, it’s harder to create new templates that work with a general-purpose SSG than write my own simpler site-specific SSG. It’s miserable to write programs in template languages. My SSG can keep the logic in the templates to a minimum, and do all the fiddly stuff in Rust. (Which is not very fiddly, because my site doesn’t have complicated navigation – compared to the multilevel menus on www.dns.cam.ac.uk for instance.) markdown ingestion There are a few things to do to each Markdown file: split off and deserialize the YAML frontmatter find the <cut> or <toc> marker that indicates the end of the teaser / where the table of contents should be inserted augment headings with self-linking anchors (which are also used by the ToC) Before this work I was using regexes to do all these jobs, because that allowed me to treat pulldown-cmark as a black box: Markdown in, HTML out. But for syntax highlighting I had to be able to find fenced code blocks. It was time to put some code into the pipeline between pulldown-cmark’s parser and renderer. And if I’m using a proper parser I can get rid of a few regexes: after some hacking, now only the YAML frontmatter is handled with a regex. Sub-heading linkification and ToC construction are fiddly and more complicated than they were before. But they are also less buggy: markup in headings actually works now! Compared to the ToC, it’s fairly simple to detect code blocks and pass them through a highlighter. You can look at my Markdown munger here. (I am not very happy with the way it uses state, but it works.) highlighting As well as the tree-sitter-highlight documentation I used femark as an example implementation. I encountered a few problems. incompatible?! I could not get the latest tree-sitter-highlight to work as described in its documentation. I thought the current tree-sitter crates were incompatible with each other! For a while I downgraded to an earlier version, but eventually I solved the problem. Where the docs say, let javascript_language = tree_sitter_javascript::language(); They should say: let javascript_language = tree_sitter::Language::new( tree_sitter_javascript::LANGUAGE ); highlight names I was offended that tree-sitter-highlight seems to expect me to hardcode a list of highlight names, without explaining where they come from or what they mean. I was doubly offended that there’s an array of STANDARD_CAPTURE_NAMES but it isn’t exported, and doesn’t match the list in the docs. You mean I have to copy and paste it? Which one?! There’s some discussion of highlight names in the tree-sitter manual’s “syntax highlighting” chapter, but that is aimed at people who are writing a tree-sitter grammar, not people who are using one. Eventually I worked out that tree_sitter_javascript::HIGHLIGHT_QUERY in the tree-sitter-highlight example corresponds to the contents of a highlights.scm file. Each @name in highlights.scm is a highlight name that I might be interested in. In principle I guess different tree-sitter grammars should use similar highlight names in their highlights.scm files? (Only to a limited extent, it turns out.) I decided the obviously correct list of highlight names is the list of every name defined in the HIGHLIGHT_QUERY. The query is just a string so I can throw a regex at it and build an array of the matches. This should make the highlighter produce <span> wrappers for as many tokens as possible in my code, which might be more than necessary but I don’t have to style them all. class names The tree-sitter-highlight crate comes with a lightly-documented HtmlRenderer, which does much of the job fairly straightforwardly. The fun part is the attribute_callback. When the HtmlRenderer is wrapping a token, it emits the start of a <span then expects the callback to append whatever HTML attributes it thinks might be appropriate. Uh, I guess I want a class="..." here? Well, the highlight names work a little bit like class names: they have dot-separated parts which tree-sitter-highlight can match more or less specifically. (However I am telling it to match all of them.) So I decided to turn each dot-separated highlight name into a space-separated class attribute. The nice thing about this is that my Rust code doesn’t need to know anything about a language’s tree-sitter grammar or its highlight query. The grammar’s highlight names become CSS class names automatically. styling code Now I can write some simple CSS to add some colours to my code. I can make type names green, code span.hilite.type { color: #aca; } If I decide builtin types should be cyan like keywords I can write, code span.hilite.type.builtin, code span.hilite.keyword { color: #9cc; } results You can look at my tree-sitter-highlight wrapper here. Getting it to work required a bit more creativity than I would have preferred, but it turned out OK. I can add support for a new language by adding a crate to Cargo.toml and a couple of lines to hilite.rs – and maybe some CSS if I have not yet covered its highlight names. (Like I just did to highlight the CSS above!) future work While writing this blog post I found myself complaining about things that I really ought to fix instead. frontmatter I might simplify the per-page source format knob so that I can use pulldown-cmark’s support for YAML frontmatter instead of a separate regex pass. This change will be easier if I can treat the html pages as Markdown without mangling them too much (is Markdown even supposed to be idempotent?). More tricky are a couple of special case pages whose source is Handlebars instead of Markdown. templates I’m not entirely happy with Handlebars. It’s a more powerful language than I need – I chose Handlebars instead of Mustache because Handlebars works neatly with serde. But it has a dynamic type system that makes the templates more error-prone than I would like. Perhaps I can find a more static Rust template system that takes advantage of the close coupling between my templates and the data structure that describes the web site. However, I like my templates to be primarily HTML with a sprinkling of insertions, not something weird that’s neither HTML nor Rust. feed style There’s no CSS in my Atom feed, so code blocks there will remain unstyled. I don’t know if feed readers accept <style> tags or if it has to be inline styles. (That would make a mess of my neat setup!) highlight quality I’m not entirely satisfied with the level of detail and consistency provided by the tree-sitter language grammars and highlight queries. For instance, in the CSS above the class names and property names have the same colour because the CSS highlights.scm gives them the same highlight name. The C grammar is good at identifying variables, but the Rust grammar is not. Oh well, I guess it’s good enough for now. At least it doesn’t involve Javascript.

22 hours ago 3 votes
Adventures in pixel space
4 hours ago 2 votes
How to simplify complex decisions by cleaving the facts

Simplify complex decisions by separating upsides from downsides, investing in upsides, vetoing with downsides, and using an appropriate decision framework.

yesterday 2 votes
The Year on Linux

I've been running Linux, Neovim, and Framework for a year now, but it easily feels like a decade or more. That's the funny thing about habits: They can be so hard to break, but once you do, they're also easily forgotten. That's how it feels having left the Apple realm after two decades inside the walled garden. It was hard for the first couple of weeks, but since then, it’s rarely crossed my mind. Humans are rigid in the short term, but flexible in the long term. Blessed are the few who can retain the grit to push through that early mental resistance and reach new maxima. That is something that gets harder with age. I can feel it. It takes more of me now to wipe a mental slate clean and start over. To go back to being a beginner. But the reward for learning something new is as satisfying as ever. But it's also why I've tried to be modest with the advocacy. I don't know if most developers are better off on Linux. I mean, I believe they are, at some utopian level, especially if they work for the web, using open source tooling. But I don't know if they are as humans with limited will or capacity for change. Of course, it's fair to say that one doesn't want to. Either because one remain a fan of Apple, in dire need of the remaining edge MacBooks retain on efficiency/battery, or simply content inside the ecosystem. There are plenty of reasons why someone might not want to change. It's not just about rigidity. Besides, it's a dead end trying to convince anyone of an alternative with the sharp end of a religious argument. That kind of crusading just seeds resentment and stubbornness. I know that all too well. What I've found to work much better is planting seeds and showing off your plowshare. Let whatever curiosity that blooms find its own way towards your blue sky. The mimetic engine of persuasion runs much cleaner anyway. And for me, it's primarily about my personal computing workbench regardless of what the world does or doesn't. It was the same with finding Ruby. It's great when others come along for the ride, but I'd also be happy taking the trip solo too. So consider this a postcard from a year into the Linux, Neovim, and Framework journey. The sun is still shining, the wind is in my hair, and the smile on my lips hasn't been this big since the earliest days of OS X.

2 days ago 2 votes
Monki Gras 2025: What I’ve Learned by Building to Last

Yesterday I gave a talk at Monki Gras 2025. This year, the theme is Sustaining Software Development Craft, and here’s the description from the conference website: The big question we want to explore is – how can we keep doing the work we do, when it sustains us, provides meaning and purpose, and sometimes pays the bills? We’re in a period of profound change, technically, politically, socially, economically, which has huge implications for us as practitioners, the makers and doers, but also for the culture at large. I did a talk about the first decade of my career, which I’ve spent working on projects that are designed to last. I’m pleased with my talk, and I got a lot of nice comments. Monki Gras is always a pleasure to attend and speak at – it’s such a lovely, friendly vibe, and the organisers James Governor and Jessica West do a great job of making it a nice day. When I left yesterday, I felt warm and fuzzy and appreciated. I also have a front-row photo of me speaking, courtesy of my dear friend Eriol Fox. Naturally, I chose my outfit to match my slides (and this blog post!). Key points How do you create something that lasts? You can’t predict the future, but there are patterns in what lasts People skills sustain a career more than technical skills Long-lasting systems cannot grow without bound; they need weeding Links/recommended reading Sibyl Schaefer presented a paper Energy, Digital Preservation, and the Climate at iPres 2024, which is about how digital preservation needs to change in anticipation of the climate crisis. This was a major inspiration for this talk. Simon Willison gave a talk Coping strategies for the serial project hoarder at DjangoCon US in 2022, which is another inspiration for me. I’m not as prolific as Simon, but I do see parallels between his approach and what I remember of Metaswitch. Most of the photos in the talk come from the Flickr Commons, a collection of historical photographs from over 100 international cultural heritage organisations. You can learn more about the Commons, browse the photos, and see who’s involved using the Commons Explorer https://commons.flickr.org/. (Which I helped to build!) Slides and notes Photo: dry stone wall building in South Wales. Taken by Wikimedia Commons user TR001, used under CC BY‑SA 3.0. [Make introductory remarks; name and pronouns; mention slides on my website] I’ve been a software developer for ten years, and I’ve spent my career working on projects that are designed to last – first telecoms and networking, now cultural heritage – so when I heard this year’s theme “sustaining craft”, I thought about creating things that last a long time. The key question I want to address in this talk is how do you create something that lasts? I want to share a few thoughts I’ve had from working on decade- and century-scale projects. Part of this is about how we sustain ourselves as software developers, as the individuals who create software, especially with the skill threat of AI and the shifting landscape of funding software. I also want to go broader, and talk about how we sustain the craft, the skill, the projects. Let’s go through my career, and see what we can learn. Photo: women working at a Bell System telephone switchboard. From the U.S. National Archives, no known copyright restrictions. My first software developer job was at a company called Metaswitch. Not a household name, they made telecoms equipment, and you’d probably have heard of their customers. They sold equipment to carriers like AT&T, Vodafone, and O2, who’d use that equipment to sell you telephone service. Telecoms infrastructure is designed to last a long time. I spent most of my time at Metaswitch working with BGP, a routing protocol designed on a pair of napkins in 1989. BGP is sometimes known as the "two-napkin protocol", because of the two napkins on which Kirk Lougheed and Yakov Rekhter wrote the original design. From the Computer History Museum. These are those napkins. This design is basically still the backbone of the Internet. A lot of the building blocks of the telephone network and the Internet are fundamentally the same today as when they were created. I was working in a codebase that had been actively developed for most of my life, and was expected to outlast me. This was my first job so I didn’t really appreciate it at the time, but Metaswitch did a lot of stuff designed to keep that codebase going, to sustain it into the future. Let’s talk about a few of them. Photo: a programmer testing electronic equipment. From the San Diego Air & Space Museum Archives, no known copyright restrictions. Metaswitch was very careful about adopting new technologies. Most of their code was written in C, a little C++, and Rust was being adopted very slowly. They didn’t add new technology quickly. Anything they add, they have to support for a long time – so they wanted to pick technologies that weren’t a flash in the pan. I learnt about something called “the Lindy effect” – this is the idea that any technology is about halfway through its expected life. An open-source library that’s been developed for decades? That’ll probably be around a while longer. A brand new JavaScript framework? That’s a riskier long-term bet. The Lindy effect is about how software that’s been around a long time has already proven its staying power. And talking of AI specifically – I’ve been waiting for things to settle. There’s so much churn and change in this space, if I’d learnt a tool six months ago, most of that would be obsolete today. I don’t hate AI, I love that people are trying all these new tools – but I’m tired and I learning new things is exhausting. I’m waiting for things to calm down before really diving deep on these tools. Metaswitch was very cautious about third-party code, and they didn’t have much of it. Again, anything they use will have to be supported for a long time – is that third-party code, that open-source project stick around? They preferred to take the short-term hit of writing their own code, but then having complete control over it. To give you some idea of how seriously they took this: every third-party dependency had to be reviewed and vetted by lawyers before it could be added to the codebase. Imagine doing that for a modern Node.js project! They had a lot of safety nets. Manual and automated testing, a dedicated QA team, lots of checks and reviews. These were large codebases which had to be reliable. Long-lived systems can’t afford to “move fast and break things”. This was a lot of extra work, but it meant more stability, less churn, and not much risk of outside influences breaking things. This isn’t the only way to build software – Metaswitch is at one extreme of a spectrum – but it did seem to work. I think this is a lesson for building software, but also in what we choose to learn as individuals. Focusing on software that’s likely to last means less churn in our careers. If you learn the fundamentals of the web today, that knowledge will still be useful in five years. If you learn the JavaScript framework du jour? Maybe less so. How do you know what’s going to last? That’s the key question! It’s difficult, but it’s not impossible. This is my first thought for you all: you can’t predict the future, but there are patterns in what lasts. I’ve given you some examples of coding practices that can help the longevity of a codebase, these are just a few. Maybe I have rose-tinted spectacles, but I’ve taken the lessons from Metaswitch and brought them into my current work, and I do like them. I’m careful about external dependencies, I write a lot of my own code, and I create lots of safety nets, and stuff doesn’t tend to churn so much. My code lasts because it isn’t constantly being broken by external forces. Photo: a child in nursery school cutting a plank of wood with a saw. From the Community Archives of Belleville and Hastings County, no known copyright restrictions. So that’s what the smart people were doing at Metaswitch. What was I doing? I joined Metaswitch when I was a young and twenty-something graduate, so I knew everything. I knew software development was easy, these old fuddy-duddies were making it all far too complicated, and I was gonna waltz in and show them how it was done. And obviously, that happened. (Please imagine me reading that paragraph in a very sarcastic voice.) I started doing the work, and it was a lot harder than I expected – who knew that software development was difficult? But I was coming from a background as a solo dev who’d only done hobby projects. I’d never worked in a team before. I didn’t know how to say that I was struggling, to ask for help. I kept making bold promises about what I could do, based on how quickly I thought I should be able to do the work – but I was making promises my skills couldn’t match. I kept missing self-imposed deadlines. You can do that once, but you can’t make it a habit. About six months before I left, my manager said to me “Alex, you have a reputation for being unreliable”. Photo: a boy with a pudding bowl haircut, photographed by Elinor Wiltshire, 1964. From the National Library of Ireland, no known copyright restrictions. He was right! I had such a history of making promises that I couldn’t keep, people stopped trusting me. I didn’t get to work on interesting features or the exciting projects, because nobody trusted me to deliver. That was part of why I left that job – I’d ploughed my reputation into the ground, and I needed to reset. Photo: the library stores at Wellcome Collection. Taken by Thomas SG Farnetti used under CC BY‑NC 4.0. I got that reset at Wellcome Collection, a London museum and library that some of you might know. I was working a lot with their collections, a lot of data and metadata. Wellcome Collection is building on long tradition of libraries and archives, which go back thousands of years. Long-term thinking is in their DNA. To give you one example: there’s stuff in the archive that won’t be made public until the turn of the century. Everybody who works there today will be long gone, but they assume that those records will exist in some shape or form form when that time comes, and they’re planning for those files to eventually be opened. This is century-scale thinking. Photo: Bob Hoover. From the San Diego Air & Space Museum Archives, no known copyright restrictions. When I started, I sat next to a guy called Chris. (I couldn’t find a good picture of him, but I feel like this photo captures his energy.) Chris was a senior archivist. He’d been at Wellcome Collection about twenty-five years, and there were very few people – if anyone – who knew more about the archive than he did. He absolutely knew his stuff, and he could have swaggered around like he owned the place. But he didn’t. Something I was struck by, from my very first day, was how curious and humble he was. A bit of a rarity, if you work in software. He was the experienced veteran of the organisation, but he cared about what other people had to say and wanted to learn from them. Twenty-five years in, and he still wanted to learn. He was a nice guy. He was a pleasure to work with, and I think that’s a big part of why he was able to stay in that job as long as he did. We were all quite disappointed when he left for another job! This is my second thought for you: people skills sustain a career more than technical ones. Being a pleasure to work with opens so many doors and opportunities than technical skill alone cannot. We could do another conference just on what those people skills are, but for now I just want to give you a few examples to think about. Photo: Lt.(jg.) Harriet Ida Pickens and Ens. Frances Wills, first Negro Waves to be commissioned in the US Navy. From the U.S. National Archives, no known copyright restrictions. Be a respectful and reliable teammate. You want to be seen as a safe pair of hands. Reliability isn’t about avoiding mistakes, it’s about managing expectations. If you’re consistently overpromising and underdelivering, people stop trusting you (which I learnt the hard way). If you want people to trust you, you have to keep your promises. Good teammates communicate early when things aren’t going to plan, they ask for help and offer it in return. Good teammates respect the work that went before. It’s tempting to dismiss it as “legacy”, but somebody worked hard on it, and it was the best they knew how to do – recognise that effort and skill, don’t dismiss it. Listen with curiosity and intent. My colleague Chris had decades of experience, but he never acted like he knew everything. He asked thoughtful questions and genuinely wanted to learn from everyone. So many of us aren’t really listening when we’re “listening” – we’re just waiting for the next silence, where we can interject with the next thing we’ve already thought of. We aren’t responding to what other people are saying. When we listen, we get to learn, and other people feel heard – and that makes collaboration much smoother and more enjoyable. Finally, and this is a big one: don’t give people unsolicited advice. We are very bad at this as an industry. We all have so many opinions and ideas, but sometimes, sharing isn’t caring. Feedback is only useful when somebody wants to hear it – otherwise, it feels like criticism, it feels like an attack. Saying “um, actually” when nobody asked for feedback isn’t helpful, it just puts people on the defensive. Asking whether somebody wants feedback, and what sort of feedback they want, will go a long way towards it being useful. So again: people skills sustain a career more than technical skills. There aren’t many truly solo careers in software development – we all have to work with other people – for many of us, that’s the joy of it! If you’re a nice person to work with, other people will want to work with you, to collaborate on projects, they’ll offer you opportunities, it opens doors. Your technical skills won’t sustain your career if you can’t work with other people. Photo: "The Keeper", an exhibition at the New Museum in New York. Taken by Daniel Doubrovkine, used under CC BY‑NC‑SA 4.0. When I went to Wellcome Collection, it was my first time getting up-close and personal with a library and archive, and I didn’t really know how they worked. If you’d asked me, I’d have guessed they just keep … everything? And it was gently explained to me that “No Alex, that’s hoarding.” “Your overflowing yarn stash does not count as an archive.” Big collecting institutions are actually super picky – they have guidelines about what sort of material they collect, what’s in scope, what isn’t, and they’ll aggressively reject anything that isn’t a good match. At Wellcome Collection, their remit was “the history of health and human experience”. You have medical papers? Definitely interesting! Your dad’s old pile of car magazines? Less so. Photo: a dumpster full of books that have been discarded. From brewbooks on Flickr, used under CC BY‑SA 2.0. Collecting institutions also engage in the practice of “weeding” or “deaccessioning”, which is removing material, pruning the collection. For example, in lending libraries, books will be removed from the shelves if they’ve become old, damaged, or unpopular. They may be donated, or sold, or just thrown away – but whatever happens, they’re gotten rid of. That space is reclaimed for other books. Getting rid of material is a fundamental part of professional collecting, because professionals know that storing something has an ongoing cost. They know they can’t keep everything. Photo: a box full of printed photos. From Miray Bostancı on Pexels, used under the Pexels license. This is something I think about in my current job as well. I currently work at the Flickr Foundation, where we’re thinking about how to keep Flickr’s pictures visible for 100 years. How do we preserve social media, how do we maintain our digital legacy? When we talk to people, one thing that comes up regularly is that almost everybody has too many photos. Modern smartphones have made it so easy to snap, snap, snap, and we end up with enormous libraries with thousands of images, but we can’t find the photos we care about. We can’t find the meaningful memories. We’re collecting too much stuff. Digital photos aren’t expensive to store, but we feel the cost in other ways – the cognitive load of having to deal with so many images, of having to sift through a disorganised collection. Photo: a wheelbarrow in a garden. From Hans Middendorp on Pexels, used under the Pexels license. I think there’s a lesson here for the software industry. What’s the cost of all the code that we’re keeping? We construct these enormous edifices of code, but when do we turn things off? When do we delete code? We’re more focused on new code, new ideas, new features. I’m personally quite concerned by how much generative AI has focused on writing more code, and not on dealing with the code we already have. Code is text, so it’s cheap to store, but it still has a cost – it’s more cognitive load, more maintenance, more room for bugs and vulnerabilities. We can keep all our software forever, but we shouldn’t. Photo: Open Garbage Dump on Highway 112, North of San Sebastian. Taken by John Vachon, 1973. From the U.S. National Archives no known copyright restrictions. I think this is going to become a bigger issue for us. We live in an era of abundance, where we can get more computing resources at the push of a button. But that can’t last forever. What happens when our current assumptions about endless compute no longer hold? The climate crisis – where’s all our electricity and hardware coming from? The economics of AI – who’s paying for all these GPU-intensive workloads? And politics – how many of us are dependent on cloud computing based in the US? How many of us feel as good about that as we did three months ago? Libraries are good at making a little go a long way, about eking out their resources, about deciding what’s a good use of resources and what’s waste. Often the people who are good with money are the people who don’t have much of it, and we have a lot of money. It’s easier to make decisions about what to prune and what to keep when things are going well – it’s harder to make decisions in an emergency. This is my third thought for you: long-lasting systems cannot grow without bound; they need weeding. It isn’t sustainable to grow forever, because eventually you get overwhelmed by the weight of everything that came before. We need to get better at writing software efficiently, at turning things off that we don’t need. It’s a skill we’ve neglected. We used to be really good at it – when computers were the size of the room, programmers could eke out every last bit of performance. We can’t do that any more, but it’s so important when building something to last, and I think it’s a skill we’ll have to re-learn soon. Photo: Val Weaver and Vera Askew running in a relay race, Brisbane, 1939. From the State Library of Queensland no known copyright restrictions. Weeding is a term that comes from the preservation world, so let’s stay there. When you talk to people who work in digital preservation, we often describe it as a relay race. There is no permanent digital media, there’s no digital parchment or stone tablets – everything we have today will be unreadable in a few decades. We’re constantly migrating from one format to another, trying to stay ahead of obsolete technology. Software is also a bit of a relay race – there is no “write it once and you’re done”. We’re constantly upgrading, editing, improving. And that can be frustrating, but it also means have regular opportunities to learn and improve. We have that chance to reflect, to do things better. Photo: Broken computer monitor found in the woods. By Jeff Myers on Flickr, used under CC BY‑NC 2.0. I think we do our best reflections when computers go bust. When something goes wrong, we spring into action – we do retrospectives, root cause analysis, we work out what went wrong and how to stop it happening again. This is a great way to build software that lasts, to make it more resilient. It’s a period of intense reflection – what went wrong, how do we stop it happening again? What I’ve noticed is that the best systems are doing this sort of reflection all the time – they aren’t waiting for something to go wrong. They know that prevention is better than cure, and they embody it. They give themselves regular time to reflect, to think about what’s working and what’s not – and when we do, great stuff can happen. Photo: Statue of Astrid Lindgren. By Tobias Barz on Flickr, used under CC BY‑ND 2.0. I want to give you one more example. As a sidebar to my day job, I’ve been writing a blog for thirteen years. It’s the longest job – asterisk – I’ve ever had. The indie web is still cool! A lot of what I write, especially when I was starting, was sharing bits of code. “Here’s something I wrote, here’s what it does, here’s how it works and why it’s cool.” Writing about my code has been an incredible learning experience. You might know have heard the saying “ask a developer to review 5 lines of code, she’ll find 5 issues, ask her to review 500 lines and she’ll say it looks good”. When I sit back and deeply read and explain short snippets of my code, I see how to do things better. I get better at programming. Writing this blog has single-handedly had the biggest impact on my skill as a programmer. Photo: Midnight sun in Advent Bay, Spitzbergen, Norway. From the Library of Congress, no known copyright restrictions. There are so many ways to reflect on our work, opportunities to look back and ask how we can do better – but we have to make the most of them. I think we are, in some ways, very lucky that our work isn’t set in stone, that we do keep doing the same thing, that we have the opportunity to do better. Writing this talk has been, in some sense, a reflection on the first decade of my career, and it’s made me think about what I want the next decade to look like. In this talk, I’ve tried to distill some of those things, tried to give you some of the ideas that I want to keep, that I think will help my career and my software to last. Be careful about what you create, what you keep, and how you interact with other people. That care, that process of reflection – that is what creates things that last. [If the formatting of this post looks odd in your feed reader, visit the original article]

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