### What could be reasons for latex() output to stop working?

In the past i used the `latex()`

output to generate latex source to use in my paper. This stopped working at some point, on three independent linux systems. Even sage scripts that produced such latex source code in the past don't do so anymore.

for example

```
epsilon_0 = var('epsilon_0', latex_name=r'\varepsilon_0')
latex(epsilon_0)
```

produces no output, not on the command line nor in my emacs *Sage* output buffer.

I assume i must have broken something. Where can I look? i use debian, and the debian sage packages to install and use ~~sage.~~sage.

Edit: correction: on two of the three system the latex() command does nothing, on the third it works. I can use that third system to generate the latex source for now. But it would be swell to fix on the other systems, too. The third system where it works is an Ubuntu, where i installed sage from source.