Let's say I have file without execution permission. Now a quick way to open such a file over the CLI is to use xdg-open which uses the system default to open a specific file.
Is it now possible to open files without running permission directly without stating xdg-open?
For example:
./test.pdf
should then open the viewer in case that file doesn't have excecution permission.
Simply put; no.
Files do not 'run', especially not PDF files. The closest you can get is to replace xdg-open with the specific name of the program you want to have started:
evince ./file.pdf
The xdg-open command simplifies this, though, by making use of configured mime types.
Going a bit further, bash scripts work like this because they contain a shebang declaration, which tells the system which program to use to open it (for bash scripts it'd be the bash interpreter). PDFs do not contain this information.
I think you can achieve this in some shells. Compare Does bash have a hook that is run before executing a command?
This link may not be the best because in bash it's not as easy as you wish. However it mentions preexec from zsh. My point is: in some shells you can analyze the command line in your own way and take your own actions.
