Add picture to speed tests post.

content/posts/2026/disk_speeds/index.md

@@ -14,6 +14,8 @@ tags:
   - photography
 ---
 
+{{< figure src="cfexpress_type_b_card.jpg" >}}
+
 I've been looking for a card reader for my CFexpress Type B cards that I use in
 my camera. There are not very many devices on the market, but they have a large
 price span: around 10x.
@@ -41,6 +43,21 @@ I did not want to overcomplicate things, just get an impression if there are any
 differences between card readers or not. Therefore I decided to perform
 sequential read and write tests using `dd` as described at [Baeldung.com][].
 
+These are the commands that I used in [Fish][] shell; Bash has slightly
+different syntax.
+
+```fish
+#!/usr/bin/fish
+echo "*** Sequential write test ***"
+for i in (seq 1 5); dd if=/dev/zero of=/run/media/daniel/NIKON\ Z6_3/tempfile bs=1M count=1024 conv=fdatasync; end
+echo
+echo "*** Sequential read test ***"
+for in in (seq 1 5); sudo sh -c "/usr/bin/echo 3 > /proc/sys/vm/drop_caches" && dd if=/run/media/daniel/NIKON\ Z6_3/tempfile of=/dev/null bs=1M count=1024; end
+rm /run/media/daniel/NIKON\ Z6_3/tempfile
+```
+
+## Results
+
 The graph below shows the means and standard deviations of 5 tests for each
 device. The "direct" label denotes tests with the card reader attached directly
 to a USB-C/USB 3.2 Gen 2 port of my [Thinkpad P14s][] laptop, rather than via
@@ -105,6 +122,7 @@ build, and the UGREEN reader is a strong contender when it comes to small size.
 
 [baeldung.com]: https://www.baeldung.com/linux/disk-performance-test
 [darktable]: https://darktable.org
+[Fish]: https://fishshell.com
 [local-copies]: https://docs.darktable.org/usermanual/development/en/overview/sidecar-files/local-copies/
 [Thinkpad P14s]: {{< relref "p14s" >}}
 [Wikipedia article on USB 3.2]: https://en.wikipedia.org/wiki/USB_3.0#3.2