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Consultant F.A.Q.

Here are some of the questions I received while I am working as a consultant in the CS labs of McGill:

1. I cannot run Firefox: A message appears saying that my current application is already in use.
Solution 1: try clean-firefox in a terminal
Solution 2: try deleting the two files “lock” and “.parentlock” in ~/.mozilla/firefox/[Profile name]/
Solution 3: go to ~/.mozilla/firefox/, and open file profiles.ini. Delete everything after the line [Profile0]
Path=0fk7gt7v.default ...
Save and rerun firefox.

2. I am trying to open Eclipse but it says that my directory is already in use.
Solution: delete the file .lock located in .metadata

3. How do I change my shell to be bash.
Solution: look at the shell you want to use in /etc/shells. Somehow, I think students are restricted to /usr/local/bin/tsch, /usr/local/bin/bash, /usr/local/bin/rbash. Am I wrong?
Then, ssh mimi and passwd -r nis -e U (where U is your username)
See for more info.

4. In the open area, there the xwindow is XFCE. How do I change it to gnome or kde?
Solution: open ~/.xsession and change uncomment XWINMGR=your_window_manager and add your window manager. It can be: gnome-session, startkde, fvwm2, twm or wmaker... see

5. This one is related to disk space. It is more as a tip on using UNIX commands! I myself had to go over some example to remember these commands:

One very cool command:
du: summarize disk usage (pretty boring by itself) but used with options is very interesting:
-k: display output in kilobytes
-s: display disk usage for sum of the directories
-h: display B, M, K for us to read easily.

Also, often enough the problem is that we don't know which folders we can delete.
First, type du -ksh .* to see all the folders starting with . .
Then there might be .mozilla and. java taking lots of space.
There are two ways to delete the cache from .java folder.
First in a shell type: ControlPanel
This will fire up the Java Plug-in Control panel. Then under the Cache tab, click CLEAR.
This will clear the .cache folder in .java.
The second way is to manually go into .java folder and mess around with it. (at your own risks)
After digging a bit, I believe that it is possible to delete some folders like:
.thumbnails --> contains old and temporary images
.wapi --> files related to .ifolder,


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