I’m working on a (private) plugin for Homebridge. So far I have been using Blink Shell to ssh into my (headless) Raspberry Pi from my iPad Pro and editing files with vi. Quite a PITA, so now I’m looking for a nice iOS editor which allows me to edit files on the iPad and seamlessly sync them to the Raspberry Pi (via SFTP?). I found a few, but all are more expensive than a (single) cup of coffee, so your advice is welcome before I buy any:
I like Textastic for what little editing I do, and it seems to fit your needs. S/FTP and RegEx support is there. Also supports WebDav, Dropbox, Google Drive…
Beats vi any day of the week
That said, I have heard a lot of great things about Coda as well. Just a bit more of power tool than I need.
Using this App I learned that editing files stored on the Raspberry Pi on my iPad via SFTP works pretty well.
Unfortunately the App has no Working Copy support and physical keyboard support seems limited, so I will still need to switch to one of the paid Apps.
I don’t mind paying for a good App that adds convenience/value to what I do, but this is the kind of situation where I wish the App Store had trials, so I could try all these Apps and then purchase the one that fits my needs best.