||Hopper FAQ |
Q. What is Hopper?
A. Hopper is a powerful, interactive, cross-platform tool for performing file
management and data transfer tasks. Through Hopper's graphical interface, a user
can perform operations on files and directories that reside on the local host,
on remote hosts, and on remote resources such as HPSS.
Q. How do I submit feature requests, bug reports, or other feedback?
A. Send feature requests and feedback to email@example.com Problems
should be reported to the LC Hotline, 925-422-4531 or firstname.lastname@example.org.
Q. Will Hopper run on my Mac/PC/Unix desktop?
A. Probably. Hopper runs on Mac OS X, Windows NT/2000/XP, and most variants of
Unix. Basically, any platform that supports Java JDK 1.4 or later will likely
Q. How do I open multiple windows to one host?
A. There are several ways to do this. To open another window displaying the same
directory, just choose the "Display in New Window"
option from the File menu. To create a new window showing a sub-directory, single-click
the middle mouse button on the icon or name of the directory you want to display
in another window. This opens a new window displaying that directory's contents.
You can also use the right mouse button over a directory entry and choose "Display
in New Window" from the menu. (On systems with a one-button mouse, a right click
can be generated by holding the Control or Command key down while clicking the
Q. How do I transfer files or directories?
A. Transferring files and directories is done via drag and drop. Use the mouse
to select the items you want to transfer, click and hold the left mouse button,
drag the cursor to the destination of your transfer in another window, then release
the mouse button. The cursor should change to a "happy face" when you're over
a valid destination. Once you release the cursor a menu will pop-up showing your
"Copy Here" to initiate the copy.
Q. How do I move files rather than copy them?
A. Follow the directions from above for copying, but choose "Move Here" from
the drop menu. Note that moves are only possible within a given host. I.e., you
cannot move files from one host to another. If you need this behavior you can
copy the files and then delete the originals.
Q. When in tree view, how do I copy into a sub-directory?
A. In tree view you must drag onto the folder icon of the sub-directory when
you want to move or copy into it. Unlike in tabular view, dragging onto the neighboring
whitespace is not adequate. A useful hint is to look for the folder icon turning
red during the drag operation; this indicates that "dropping" there will deposit
items into that folder.
Q. How do I get more information about my file transfer?
A. Within the Transfer Manager window, either double click on the transfer's
status line, or single click on it and press the Details button.
Q. How do I interrupt a transfer or other operation?
A. To interrupt file transfers, select the line of interest in the Transfer Manager
dialog, then click the Abort button. To interrupt other types of operations,
press the red Stop button. Note that some actions are not interruptible, and
will be indicated by the Stop button being disabled (grayed out).
Q. How do I select more than one file or directory?
A. In the tabular display mode, click on the first item of interest and Control-click
on any additional items you wish to select. If you want to select contiguous
items, click in the white space following a file or directory name and sweep
the cursor up, down, or to the side to select a range. Selections in the detailed
display mode are similar, but you can also extend a selection by Shift-clicking.
If you want to select all items, choose "Select All" from the Select menu. (On
a Mac, use the Command key instead of Control.)
Q. How do I synchronize two directories?
A. Hopper can now perform rsync-style directory synchronization operations. This
uses rsync when it is available, and uses built-in logic for doing synchronize
operations involving hosts that do not support rsync. For example, suppose we
want to synchronize from directory DirA on host HostA to directory DirB on host
HostB. To do this, first open directory windows for both HostA and HostB. Select
DirA on HostA and drag it atop the directory icon or name for DirB on HostB.
From the resulting pop-up menu, choose "Synchronize this Directory".
Before a synchronization operation is actually invoked, a tabbed dialog is displayed
that describes the operation and allows you to set various options. Take a look
at the Function tab, which is of particular interest. Note that you can perform
a dry run.
Once a synchronization operation is underway, it is run in the background as
a file transfer job. Use the Transfer Manager window to keep track of the synchronization
job. As with any file transfer job, the Transfer Manager allows you to display
a file transfer monitor window so you can view details of the transfer (and this
is where you can view results of dry runs).
Q. What is the "C" button? What do you mean by "caching".
A. The "C" button toggles directory caching. When active, a directory's content
information is cached in memory for use during that session. This removes the
need for a directory listing operation the next time a previously visited directory
is displayed. This can be useful when connected to very slow remote systems.
Even when caching is on, Hopper will get a new listing if it knows the cached
directory changed. When caching is off, a fresh directory listing is generated
each time a directory is visited.
Q. How can I make Hopper use scp for file transfers?
A. By default, Hopper uses sftp for performing secure file transfers. There are
a number of good reasons for this, including better throughput and fewer authentications.
If you need to use scp, though, just open the Operations->File Transfer preferences
and select the
"Use SCP if possible" option.
Q. How do I tell Hopper to pass command line flags to ssh, scp,
A. Simply enter the command line flags following the executable names in the
Connection->SSH preferences. For instance, if you're using certain versions of
OpenSSH clients and want to force protocol-1 to be used, set the ssh path preference
to "ssh -1".
Q. How should I connect to storage (HPSS)?
A. Using the "Connect to Storage" item from the Connect menu will use the best
available technique for connecting to storage from the given host. On LLNL production
hosts there are three choices for connecting to storage: Storage, NFT, and FTP.
The Storage option utilizes the HPSS client API, and provides a full- featured
interface to storage. This includes changing permissions and group values. Transfers
from production machines use parallel FTP. The NFT option is comparable to the
NFT command line client; performance is slower than HPSS for some operations,
but transfers are parallel and persistent. The FTP option uses standard, serial
FTP transfers, and offers a reduced set of functionality.
Q. Why do my xterm windows go away when I exit Hopper?
A. By default, xterm windows launched via Hopper will persist after Hopper exits.
However, this behavior can be changed via the "Preserve remote xterms" item in
the Operations Dialogs -> Launch Xterm preferences. If your xterms are going
away against your wishes, restore this preference to the factory setting.
Q. How can I make Hopper correctly display or operate on directory
names which contain Unicode characters?
A. On some Unix-based systems, setting an environment variable that defines localization
will allow Hopper to display and/or operate on Latin Unicode paths correctly.
Try setting LC_CTYPE to "en_US.UTF-8"
before launching Hopper. This should work on many Unix systems, but on some it
will be ignored, and on others it may slow Hopper interactivity.
Q. How can I find out what's going on behind the scenes with
A. Hopper is a very complex application and often manages multiple connections
and dozens of threads. The "Audit Manager" window (via the Windows menu) lets
you see what Hopper is really doing. The Actions tab shows all of the high-level
commands executed by Hopper, including transfers and other directory operations.
The Connections tab shows all of the connections being managed by Hopper, including
active and inactive (cached) ones. The Passwords tab shows information related
to password prompts -- e.g., who is asking for a password and why.
Q. Something went wrong. Where do I find the error messages?
A. If an error occurs during a non-transfer operation, Hopper's status field
will say "ERROR -- CLICK HERE FOR DETAILS". Clicking on that message will bring
up the diagnostics window, which you can get to at any time via the Windows menu.
If an error occurs during a file transfer, information is displayed in the Transfer
Manager window, also available via the Windows menu. If an error occurs during
a search, see the Search Manager window.
Q. Why can't Hopper connect to [host]?
A. First, make sure that the host is up and accepting connections by trying to
connect manually. (Use the same option you tried in Hopper -- e.g., if you tried
to open an ssh connection in Hopper try running
"ssh host" from a shell window.) If the manual connection works, double check
your "Connection Types" preferences to make sure everything is correct. For failed
ftp connections, try changing the
"passive mode" preference value. If you're still stuck, contact the LC Hotline.
Q. I'm getting fewer (or more) password prompts than I expected.
A. Hopper does a lot of work to reduce the password prompts you see; freed connections
are cached and re-used and authentication information is stored during the session
and re-used whenever possible. However, Hopper is a highly concurrent application;
you can start one transfer, manipulate files in the source or sink window during
the transfer, and even start additional transfers. The price for this flexibility
is that multiple connections are required. In most cases, you'll only have to
enter your password for a given host just once. In the worst case, however, a
password prompt is required for each connection.
On systems that support it, you can reduce password prompts by setting up SSH
keys. There are some cases when using scp transfers that you will have to authenticate
frequently, possibly once per file moved. For this reason we set the default
secure transfer mode to sftp, and encourage its use.
Q. Hopper sometimes slows down if I run it on a remote host and
display it locally. Why?
A. Hopper performs well on local and most remote systems. Slowdowns are usually
caused by the remote host being heavily loaded (check the load average reported
by the Unix 'uptime' command.) Also, we've seen some versions of SSH that perform
poorly when tunneling X11. Java applications are particularly sensitive to SSH's
implementation of X tunneling. OpenSSH versions other than 3.6p1 seem to have
the best X tunneling performance. One way to speed up X11 applications is to
disable X tunneling, such as with the xauth application. Note that when SSH X
tunneling is bypassed any passwords entered via Hopper will be sent in the clear
over the network.
Q. Double-clicking on the Hopper jar file on my Windows system
does not launch Hopper, even though I have the proper Java installed. Why not?
A. Windows systems usually have an association between jar files and java, such
that double clicking on a jar file launches java. This is not always set up,
though, especially on XP. For this reason we now distribute Hopper as a self-contained
exe file for Windows to avoid these potential issues. The exe file also verifies
that a recent-enough version of java is available.
Q. I'm seeing really odd looking windows when I run Hopper on
a remote system and displaying it with X11 on my Mac. Why?
A. We've seen this behavior on Macs running OS X 10.4 (or later) when the connection
to the remote system was made with ssh. X11 tunneling behavior changed in recent
versions of OpenSSH, causing problems when connecting to some older servers.
To preserve backward compatibility, use the -Y command line option when making
an ssh connection. E.g.,
"ssh -Y hostname". Note that related problems can occur on non-Macs running newer
versions of OpenSSH; use the -X or -Y command line flag to work around the problem,
depending on the version of ssh client you're using.
Q. Why doesn't the "Launch Xterm" button work on the Mac?
A. It will work, but requires some set-up. There are three things to check. The
first needs to be done each time you run Hopper. The last two need only be done
- Make sure the "X Window System" application (usually at /Applications/Utilities/X11)
- Make sure ssh is set up to forward X11. This can be done by adding a command
line option in the Hopper preference for ssh (Preferences->Connections->SSH->Path
of ssh). For Macs running OS X 10.4 or higher, set this to "ssh -Y". For Macs
using an older OS, set this to "ssh -X".
- Make sure your DISPLAY environment variable is set by running this command
in a terminal window:
~/.MacOSX/environment "DISPLAY" ":0.0"
After executing this command, log out and log back in again, and Hopper should
be able to launch local and remote Xterm windows.
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