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Listing Directories

Virtual directories may be listed using the als command or vls. als produces straightforward output similar to that produced by the standard UNIX ls utility. We recommend its use. vls produces more complex output and is more useful for maintaining directories than for exploring them. Of course, if one is interested in browsing, in our opinion invoking the menu broswer program on the current directory (to do this, invoke it as menu .) gives one the most straightforward user interface.

    vls [-A, -a,-c,-f,-i,-u,-v] [ -A attribute ] [-a attribute ] [path]

vls takes the virtual path name for a file or directory. If the path is for a directory, the links within that directory are displayed. If the path is for any other type of object, then the information for the named link is displayed.

By default, vls displays for each link the link name (i.e., the local component of the path name) and the target of the link. The target of the link is generally a host and a name relative to that host.gif Some special characters may precede the link name; their meanings are:

This is a union link (always to a DIRECTORY or DIRECTORY+FILE). Usually only shown if -u flag was specified, unless expanding the link failed.
for an invisible link (only shown if -i flag specified) (could be to a FILE, DIRECTORY, or DIRECTORY+FILE).
blank (' ')
if a normal link to a FILE.
for EXTERNAL (to an object on a host that does not run Prospero)
for NULL (returned if inadequate permissions),
for OBJECT (neither a DIRECTORY nor a FILE, just something that can have attributes associated with it.)
Indicates that a filter is associated with the link.
Expanding this union link failed.

The -v option causes the object type, and the type of each field to be displayed, and it lists the filters associated with the link. It also prevents the truncation of fields that are too long to be cleanly displayed without the -v option.

The -u option indicates that union links are not to be expanded. By default, union links are expanded, and the results of that expansion displayed. To see which union links are included in a directory, the -u option must be specified.

The -i option indicates that invisible links should be displayed; they are normally not.

The -d flag indicates that even if the path argument to vls is a directory, we want to look at that link instead of looking at the contents of the directory. It is just like the -d flag to the UNIX ls command.

There are cases when a directory might include more than one link with the same name. One way this can happen is if the directory contains union links. By default, only the first link with a particular name is displayed. The -c option tells vls to display all links, including those with conflicting names. The name of conflicting links will be followed by a ``#'' and a number that allows them to be uniquely identified.

The -f option causes union links which could not be expanded to be displayed. This option is presently set by default.

The -a option indicates that the attributes associated with each object pointed to by the link are to be displayed. It also forces the verbose option. If only a particular attribute is desired, the attribute can be specified as part of the -a option itself (e.g. -aFORWARDING-POINTER). The -a option by itself displays all attributes. The -A option is similar to the -a option, but it only lists the attributes associated with the link itself, not those associated with the object referenced by the linkgif.

next up previous contents
Next: Moving Around Up: The Commands Previous: vrm

Padma Indraganti
Tue Jul 9 11:37:24 PDT 1996