shell-scripting on S Anand

Things I Learned - 08 Feb 2026

Sun, 08 Feb 2026 00:00:00 +0000

This week, I learned:

The Disconnected Git Workflow explains how to use the git send-email workflow. That’s like using email instead of GitHub as the collaboration mechanism - decentralizing and reducing dependencies.
Grok throws a HTTP 431 when you pass it a query over 6,890 characters in the URL. Here’s an example with 6,900 characters.
As of now, there’s no way to tell uv to use the cache and install only missing repos (#15454). But this is Deno’s default behavior, making Deno a slightly better choice in this regard.
Shelling Out Sucks shares common pitfalls when calling the shell from programs. Suggestion: Shell-escape ALL inputs. Use set -o pipefail to detect failures in the middle of a pipe chain. Explicitly check the error code, not just stderr.
dax, which is based on zx, is a simpler Deno-based alternative to shell scripts. See examples. ChatGPT. However, scripting language matters more when humans maintain shell scripts. Since I’m using AI, it’s easier to use bash scripts and let it handle any complexities.
git push --force-with-lease is like git push --force but won’t overwrite if others have pushed in the meantime. Default to this instead of --force – it’s safer.
Microsoft’s docfind generates a WASM search index for documents, building a dependency free browser based compact and fast search.
diffs seems a promising library for rendering diffs in the browser.
Genie 3 seems pretty good. We should expect to see World Models becoming usable in a few months.

Pipes May Be All You Need

Sat, 05 Jul 2025 11:49:24 +0000

Switching to a Linux machine has advantages. My thinking’s moving from apps to pipes.

I wanted a spaced repetition app to remind me quotes from my notes. I began by writing a prompt for Claude Code:

Write a program that I can run like uv run recall.py --files 10 --lines 200 --model gpt-4.1-mini [PATHS...] that suggests points from my notes to recall. It should

--files 10: Pick the 10 latest files from the PATHs (defaulting to ~/Dropbox/notes)
--lines 200: Take the top 200 lines (which usually have the latest information)
--model gpt-4.1-mini: Pass it to this model and ask it to summarize points to recall

Then I realized that I could do this on the CLI:

find ~/Dropbox/notes -type f -printf "%T@ %p\n" \   # Print the timestamp and file path
  | sort -nr \                                      # Sort latest first
  | head -n 10 \                                    # Pick the 10 latest files
  | cut -d" " -f2- \                                # Drop the timestamp, just get paths
  | xargs -I {} head -n 200 "{}" \                  # Get the first 200 lines
  | llm -s "List 3 points to remember"              # Ask an LLM to share points to recall

This works well!

Hosting options

Sat, 01 Jun 2013 05:48:55 +0000

I've been trying out a number of options for hosting recently, and have settled on Amazon spot instances.

Here were my options:

Application hosting, like Google AppEngine. I used this a lot until 2 years ago. Then they changed their pricing, and I realised what “lock-in” means. I can’t just take that code and move it to another server. Besides, I’m a bit wary of Google pulling the plug. Heroku? Same problem. I just want to take the code elsewhere and run it.
Shared hosting, like Hostgator. This blog is run on Hostgator and I’m extremely happy with them. But the trouble is, with shared hosting, I don’t get to run long-running processes on any ports I like.
Run you own servers. The problem here is quite simple: power cuts in India.
Dedicated hosting, like Amazon EC2, Azure, GCE, etc. This remains as pretty much the main hosting option

I’m a price optimisation freak. So I ran the numbers for a year’s worth of usage. I was looking at the CPU cost of a large machine with 7-8GB RAM. Bandwidth and storage are negligible. The cost per hour worked out to:

Amazon: $0.32 / hr in Singapore, $0.24 in Virginia
Google: $0.29 / hr in Europe
Microsoft: $0.32 / hr in US

The price is not all that different, but I need low latency, so Singapore it what it’ll have to be.

EC2 location	Latency (ms)
Singapore	139
Oregon, US	334
Japan	517
Ireland	618
Australia	620
California, US	677
Virginia, US	710

Now comes the choice of the right model. At $0.32 per hour, that’s $230 a month.

Amazon offers some ways of getting this down. Instead of on-demand instances, I could go for reserved instances. For a year of usage, that’d get the price down to about $131 a month, nearly halving it. ($739 upfront for a heavy utilisation large reserved instance, with $0.095 * 24 * 365.25 for the year.)

In this case, I know I’ll need the servers for a year. Probably more, but then, I might want to switch later. So this isn’t a bad move. But we can do better. Amazon also offers spot instances. Spot instances might get shut down any time – but in reality, so can on-demand instances. I need to plan for it anyway. I’m not going to host anything that’s so sensitive that if it’s down for a few hours, I’ll have a problem.

But what’s attractive is the pricing. Typically, it’s $0.04 per hour, making it about $29 per month. Even if it shoots up to twice that, at $58, it’s less than a fourth of the on-demand price and less than half the reserved instance price.

I’ve managed to script the entire setup up sequence as shell scripts, and it takes less than an hour to get a new server up and running the software I need. I need to work out a decent backup mechanism. Plus, I could use more reliable storage like like Amazon’s EBS to preserve the data. But on the whole, the pricing is far too attractive and makes the risks worthwhile.

Comments

Anand Chitipothu 2 Jun 2013 3:36 pm: Did you look at Linode? I’ve been using Linode for couple of years and pretty happy with it. The 8GB RAM model costs about $160 per month. Sadly, they don’t have a data center in Singapore. You can test the download speeds and latency of their data centers from https://www.linode.com/speedtest/.
jouko 7 Jul 2013 4:21 pm: I am using Inmotion hosting for my blog. May be i should also shift to amazon cloud.
S Anand 3 Jun 2013 7:30 am: I did try Linode early on, and it’s a fairly decent option. It’s just that for my needs, the $29/month that I can get with Amazon is too attractive.
Amit Chakradeo 3 Jun 2013 8:33 pm: If you don’t mind occasional downtimes and occasional ummm complete loss of data :-), you can consider low end VPS boxes. (http://lowendbox.com/) You can find some decent deals if you check out the posts there…
Sriram 15 Jan 2014 4:18 pm: have u tried openshift ?