Another achievement I unlocked with the recent website update is the newsletter switch from Substack to a fantastic and independent provider, Buttondown. That required updating all the “subscribe to my newsletter” links. We’re talking 5K posts, all saved as individual files in the same directory. The bash command that did that for me is:

find content/post/*.md -type f -exec \
    sed -i .bak 's|https://nicolaiarocci.substack.com|https://buttondown.email/nicolaiarocci|g' {} +

It is pretty straightforward. find looks for all markdown files in the content/post/ directory. On each file, sed performs a search-and-replace action. Notice that I use | instead of the standard / as a separator for the search-and-replace pattern , and that’s because the pattern itself has /s in the URLs so I need to differentiate. Also, on macOS, the -i parameter requires a backup file argument ("*.bak") to make a backup copy before the update. This argument is unnecessary in newer sed versions and will perform an in-place update if not provided.

Later, I realized I would be better off if I removed the call to action from my posts and added it to the footer template instead. That way, I’d only have one place to edit or update it in the future, and my RSS feed (and newsletter updates, as they draw from the RSS feed) would be clean of unnecessary spam. In hindsight, this a move I could’ve made many years ago (2010?) when I installed Hugo for the first time, but hey, better late than never. But how could I delete calls to action from all my 5K posts? With a variation of the above command, of course:

find content/post/*.md -type f -exec sed -i .bak '/

It is the same logic as above, but we’re replacing the matched string with a “delete all lines till the end of the file” pattern this time. I must admit that this one was trickier to pull off and required a discrete amount of trial and error.

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