R: With the command lpr.

$ lpr file_name puts the file in the ia5_ls print queue in the A5 Building.

$ lpr -Pic6_ls file_name puts the file in the ia6_ls print queue in the C6 Building.

1.2 How can I find out the state of a print queue?

R: With the command lpq

$ lpq (state of the ia5_ls queue at the A5 Building)

$ lpq -Pic6_ls (state of the ic6_ls queue at the C6 Building)

1.3 How can I cancel a job in the queue?

R: First, use the Ipq command in order to view the state of the queue you have sent the job to. You will find its job number, along with other information. In order to cancel it, type:

$ lprm -Pqueue_name job_number

A number of jobs can be cancelled at once. Just separate the job numbers with a space. In order to cancel all the jobs, type:

$ lprm -Pqueue_name -

R: The vi is Unix's own system editor, and emacs is also available. In the Xwindow environment, xedit is also available.

2.2 I am using the emacs/vi editor. When I try to save, I get a message saying I have too little disk space. How can I solve this problem?

R: Press <Ctrl>+Z. This leaves the editor running in the background. Next, erase all the files on your account that are not necessary, with the command rm.

Then use the jobs command in order to determine the process number for the editor you left running in the background. If you type fg %<process_number> you will go back to the editor.

2.3 How can I quit vi without saving?

R: With :q!

R: $ ps -fu <user_name>

3.2 What do I do to "kill" the tasks?

R: Firstly, type: $ ps -fu <user_name>. You will see a list of the tasks and their corresponding PID (process ID). In order to eliminate any of them, just type: $ kill -9 <PID number>

3.3 How do I run a command in the background?

R: $ <command_name> &

3.4 I have compiled a program, and obtained an executable file, but it won't run. I get the message: "command not found". I have given the file execution permission with the chmod command. What could still be going wrong?

R: Your executable may not be in any of the folders specified in the path variable. In order to run it, you will need to change the path file so that it includes the folder where you have the executable. Alternatively, type:

$ ./<executable_name>

In this way, we are indicating that we want to run the file situated in the current directory.

3.5 How can I change the path?

R: This depends on the version of Unix and the shell you are using.

 
tcsh: (in the .login, .tcshrc or .cshrc files) 
       $ set path=( paths separated by a space ) 
  or 
       $ setenv PATH "paths:separated:by:a:colon" 
sh:   (in the .profile file) 
       $ PATH

You can use $PATH or $path for all these commands, in order to reference the variable's previous value.

R: This depends on the version of Unix you are using:

Alabi/Alaba: $ vquota -u

If nothing appears, (while in Alabi, for example), login to another machine (running Alaba) and repeat the command.

Alumbra/Ada: $ quota -v

Linux (PC): For the moment, the amount of disk space quoted is not reliable. We are working on the problem. For now, you can check this from Windows, since it's the same partition.

5.2 I'm out of disk space. Can you extend my storage allocation?

R: Disk space can generally not be extended. Only students carrying out a Final Thesis can obtain an extension if they require it. If this is the case, the student's Final Thesis supervisor must send a message to lcfibfib.upc.edu in order to justify this need to the Computing Laboratory.

5.3 Is there a folder where I can temporarily store files?

R: The Unix configuration files are the same for all machines, but their content can vary depending on the subjects for which they are used. The files are:

$HOME/.login
$HOME/.tcshrc or $HOME/.cshrc

and sometimes
$HOME/.logout
$HOME/.profile

The folder where you can find these is /etc/skel. In this folder you will find other folders named after a specific subject or software package.

Alabi/Alaba: 


/etc/skel/alumnes     basic default configuration files


/etc/skel/entorn_x    Xterminal environment configuration files

Alumbra:


/etc/skel/cam         configuration files for CAM


/etc/skel/grafics     configuration files for subjects GC, MGC and VRC

All files are accessible to users, so users can recover them themselves if there is a problem. For example: In order to copy the default .login file for working in Alabi/Alaba

Alabi>cp /etc/skel/alumnes/.login $HOME

R: Ada, Alumbra and Moonrey: gdb and ddd. Alabi/Alaba: dgx and ladebug

7.2 How do I extract the data from a .tar file?

R: $ tar -tvf <.tar_file> (In order to view contents)
$ tar -xvf <.tar_file> (In order to extract contents)

You can use wildcard characters such as * and ?.

7.3 Can I compress files in Unix in order to save disk space?

R: Yes. You can use gzip, which generates .gz files, or compress, which generates .Z files.

For more information, please use the man command.

7.4 What is the command for uncompressing .gz files?

R: $ gunzip <file_name.gz> or $ gzip -d <file_name.gz>

7.5 What is the command for uncompressing .Z files?

R: $ uncompress <file_name.Z>

R: Yes. Use the command $ script <file_name> . In order to deactivate it, use <Ctrl>+D

R: These errors occur when you cave exceeded your allocated disk space. You must delete everything that is not necessary. It is important to empty the Netscape cache folder (.netscape/cache).

9.2 How do I run Mathematica from the SunRay machines?

R: Before accessing Ada (the machine that has Mathematica installed) you must type: fonts_mathematica.

- Then connect to Ada over a secure shell: ssh ada -l username (When using a secure shell, there is no need to change the display variable).

- Then just run Mathematica.