View documents. More information: https://docs.kde.org/stable5/en/okular/okular/command-line-options.html.
okular
okular path/to/file1 path/to/file2 ...
okular --page page_number path/to/file
okular --presentation path/to/file
okular --print path/to/file
okular --find search_string path/to/file