I can’t figure out how to get the visidata frequency analysis histograms to render properly. Some render as blocks as expected but others are those diamond-question marks. I know it’s a silly hang up but it’s what’s keeping me on iterm. It’s seemingly impossible to search for (or at least I haven’t figured out the right keywords) to troubleshoot too.
Try asking on https://github.com/saulpw/visidata the community there can help.
I am seeing this issue on a Mac with ghostty but not with wezterm, from the same binary. Ghostty shows some correct characters and some diamond-question marks, and a line usually contains one or the other. The ghostty inspector shows the diamonds are not the blocks.
It calls them derived columns and you can use python to combine and process other columns.
https://www.visidata.org/docs/columns/#derived
It is also possible to create a column based on the output of a shell command.
VisiData is row based, not cell based, so you cannot create expressions that reference data across rows.