I have been using latexmk to make a pdf file in the following way:
latexmk -pdf filename.tex; open filename.pdf
This opens the pdf in Preview. However I want to open the pdf with a given zoom (problems with vision), and Preview reverts to a default zoom at every opportunity. This is annoying because I like to recompile my latex quite often.
I have tried using "open -a" with both skim.app and Adobe Acrobat Reader, because I have gained the impression from reading about these pdf viewers on the web that one can change the default viewing parameters. Unfortunately, a command line such as the one above, possibly using "open -a skim.app filename.pdf" produces the error message that either the file or the program "can’t be opened because it is from an unidentified developer". This happens whether of not I tell the system (via Command-I) to always open filename.pdf with the appropriate application (skim or Reader).
Since skim provides some kind of AppleScript access, which Preview doesn't, I wondered whether to try using AppleScript. But I need to get on with what I'm writing, rather than get into an infinite regress of things I need to learn first.
I use vim for editing, and briefly considered vim-latex, but rejected it as too complicated to 1) install and 2) learn how to use. I want no more than to open, from the command-line, a particular pdf in a pdf viewer where one can control the parameters for viewing.