General format for command 'open':
    vitis open -c|-e|-v <input data> [options]

The command is used to open files using the 'ufo' utility by default.
It is closely related to the 'vitis show' command.
To specify a custom program for opening files,
use the '--app <program>' option.

You can use the '-t' flag to run the program in foreground
(which may be important when launching console programs).
Without '--app', this flag (-t) will be used with 'ufo'.
The '-t' option for 'ufo' means opening all files
with a single application in the current terminal, with waiting.

---

vitis open -c <category> [options]
    Opens files located in the root of the specified category.
    The '--as-dir' option allows you to open the specified category
    as a directory in the default file manager.

---

vitis open -e <expression> [options]
    Opens files by expression (see 'vitis show --help' for details
    on expressions).
    The '--as-dir' option allows you to open the specified expression
    as directory in the default file manager.

---

Options affecting the generated file list (relevant for -c and -e).

The '-n' option is used to select one or more specific files from the list.
If a single number follows '-n', only that file will be opened.
You may also use an expression consisting of file indices and ranges
separated by commas (without spaces). Ranges are specified with hyphen (-).
Single indices and ranges may be mixed in the same expression.
Examples:
    vitis open -c Music -n 4-13,18,24-31
        This command opens files 4 through 13 (inclusive),
        file 18, and files 24 through 31 (inclusive).
        This is useful when you already know the file list
        (for example, after 'vitis show -c Music').

The '--sort=<type>' option specifies how the file list is sorted:
    --sort=extension - sort by file extension;
    --sort=name      - sort by file name (default);
    --sort=none      - no sorting;
    --sort=size      - sort by file size;
    --sort=time      - sort by file modification time;
    --sort=atime     - sort by file access time;
    --sort=mix       - random order.

The '--reverse' or '-r' option reverses the sort order.

---

Other options.

The '--show' option displays the file list,
as with the 'vitis show command'.

You can specify an alternative program instead of ufo
by using the '--app <program>' option.

---

vitis open -v <file> ... [-N|--note] [--app <program>] [-t] [--show]
    This command opens the specified files relative to the Vitis mount point.
    The '--show', '--app' and '-t' options (see above) are supported.
    Additional flag '-N' ('--note') opens the note of the specified file.
