Math Lab FAQ

Google Chrome is open on another session

File locking typically is a safety mechanism to ensure a file can be written to and read from by multiple processes. Google Chrome typically makes a file lock as a symbolic link to the process ID on a specific workstation host. If that link resolves to a process, then a new instance of Google Chrome does not get opened. However, the symbolic link may not have been properly written. Here's how to fix that.

Terminal Fix:

A simple command to delete this lock file will do the trick:

rm -i $HOME/google-chrome/SingletonLock

The $HOME variable will be expanded to be the username of the user who executed the command.

File Manager Fix:

Alternatively, a user can use the file manager to navigate to $HOME/google-chrome/ and remove the SingletonLock file. To navigate here, one may have to enable hidden files with a settings toggle or the Ctrl+h keyboard shortcut.

Firefox will notify a user if it believes there is another session open on a different computer. This may be the case if the previous session did not terminate gracefully.

The popup that Firefox will show may have the text "Firefox is already running, but is not responding. To use Firefox, you must first close the existing Firefox process, restart your device, or use a different profile."

Terminal Fix

The files to delete are located within the user's profile directory that is within their $HOME folder, where $HOME could be expanded to /home/nfs/username.  $HOME/.mozilla/firefox/*.default/ is a fuzzy match for Firefox's profile hash using the * glob pattern. The specific files to delete are lock and .parentlock. This one line command should remove those files:

rm -i $HOME/snap/firefox/common/.mozilla/firefox/*.default/lock

OR

rm -i $HOME/.mozilla/firefox/*.default/lock

Alternately, if the prior command doesn't work, one can try to delete all files in a user's home directory that contain the string ending with 'lock' with the following command:

find $HOME -path "*/.mozilla/*" -name "lock" -delete

File manager fix

In your preferred file manager, you are able to navigate to the directory which holds the lock on Firefox in /home/.mozilla/firefox/*.default/. If you do this, you'll note that the * blob is a random hash of numbers and letters that correspond to the profile that firefox wants to use. Since it is difficult to know what the user profile's hash is; whether they are using a default profile versus a custom profile, it is recommended to go to each folder that has default  or default-release appended.

Faced with the prospect of either putting too little on a line or too much, TeX puts too much and warns you about it. If you view the output, you should see a line that runs into the right hand margin; it will also be marked with a thick black bar in the right margin (you may have to scroll the view window to the right to see it). Sometimes the problem is that you have done something genuinely wrong; for example, if you accidentally put too much stuff in math mode (between dollar signs), TeX may not find a good place to break the line, because TeX tries to avoid breaking a line in the middle of a formula. At other times, it may be that a long word or mathematical formula happens to occur right at a desirable place for a line break. In this case you can usually rewrite the sentence slightly so the line can be accommodated. It may also be that the long word can be hyphenated, but that TeX doesn't know how to do it. In this case you can insert information telling TeX where it is acceptable to hyphenate the word. Put '\-' at every place in the word that a hyphen is acceptable, like this: ab\-at\-toir. DON'T put hyphens without the '\' in the word, as they will be inserted no matter what.

The Linux Labs are standardized with the same authentication provider as myWhitman. In other words, your Whitman login and password are the same.

If you know your password and would like to change it, the fastest method would be to use myWhitman's Password Changing tool at: https://my.whitman.edu/whitman-password