Frequently Asked Questions
How do I get a CLAS Linux account?
I can't login!
Help! I forgot my passphrase!
How do I change my passphrase?
How do I logout?
How do I switch between the GUI login window and the text login?
What software can I use?
Where can I get more information about CLAS Linux computing resources?
How can I use my CLAS Linux file space on my self-managed machine?
How do I access the CLAS Linux environment from off campus?
What machines can I login to remotely?
How can I transfer files to or from my CLAS Linux account?
What is Linux, anyway?
What's a shell?
How do I change my shell?
My backspace key doesn't work!
What are some basic Linux commands?
How do I get help for a Linux command?
How do I capture the output of a command?
How do I view file and directory permissions?
How do I run a process that will continue to run after I logout?
How can I learn more about Linux?
How do I print a file?
What are the names and locations of printers?
How do I check a print queue?
How do I cancel a print job?
How do I print to a document in color?
My document won't print!
My print job wants to use A4 paper!
How do I print from my laptop?
CLAS - College of Liberal Arts & Sciences
FAQ - Frequently Asked Questions
HawkID - Your HawkID is the identifier you use to access University-wide information services
Hawkmail - Hawkmail is the campus-wide email service provided by ITS
ITC - Instructional Technology Center
ITS - Information Technology Services
MLH - MacLean Hall
SH - Schaeffer Hall
Please send email to the Help Request Trouble Ticket System and describe the error.
See Where to Find Help.
Anyone with an active HawkID can use our automated provisioning feature that will create a College of Liberal Arts & Sciences Linux account.
You can auto-provision an account by following the Remote Linux Desktop instructions (preferred method) or by logging in with an SSH client to linux.divms.uiowa.edu (for more advanced users), which creates an account the first time you login either to our FastX Remote Linux Desktop environment or login directly via SSH.
First, check that the Caps Lock key is not on.
Next, try to login to a text-only console instead of at the graphical console. You can login to a text-only console by simultaneously pressing the Ctrl, Alt, and F1 keys. If you can login to a text-only console, check your quota with the quota -s -w command. If you are over quota, remove or compress files and directories until you are under quota again, and then try to login at the console.
You can reset your HawkID passphrase with the HawkID Reset form.
You can change your HawkID passphrase with the HawkID Change Password form.
Use the exit command to exit a text-based session. If you're logged into a graphic desktop, then on the menu across the top, click on the green icon that looks like a man running through a door.
When at a text console display, to get the graphic display back, simultaneously press the Control, Alt, and F7 keys. When at a graphic display, to change to a text console display, press and hold the Control, Alt, and F1 keys.
At a graphic desktop, you can pull down the Applications menu at the top left corner of the display and browse through the Applications menu and submenus.
From a Linux command shell, you can see all the packages installed with the operating system by entering the command rpm -qa. The command rpm -ql <packagename> will display all the files in a particular packaged named <packagename>. Commands are usually in directories named bin. Development libraries are usually in directories named lib and are often in packages that have devel or lib in their names.
Most other packages that do not come with the operating system are installed in the /opt or /usr/local directory. At a graphic desktop, you can examine the /opt or /usr/local directory with the file manager. From a command prompt, you can use the ls command.
You can also try finding a package or command by entering the command man -k <keyword>, where <keyword> is a word associated with the software you're looking for. For example, man -k compress will return a list of all commands that have something to do with compression.
More information is available here:
See the online help at Remote File Access Help.
For help with accessing the Linux environment remotely, see Starting a Remote Session.
Use the address linux.divms.uiowa.edu to login to the Linux session server. From there, you can login to any other CLAS Linux machine.
See Remote File Transfer.
A shell (also known as a command interpreter) is a program that takes input from a user and uses that information to run other programs. Some shells allow the use or aliases (or nicknames) for commonly used commands; some allow you to easily rerun a command you recently ran.
To change your shell, click Set UNIX/Linux Login Shell to go to the HawkID tools web page and change your shell. Use this with caution as your instructor may have designed their course around a specific shell (like bash, or tsch only).
If your Backspace key quits working in a text session, try stty erase ^H or stty sane.
Files and directories
pwd - print the path of the current working directory
cd - change the current working directory to a different directory
ls - list the contents of the current working directory
mkdir - create a directory
rmdir - delete a directory
cp - copy a file
mv - rename a file or directory, or move the file or directory into another directory
rm - delete a file
chmod - change file or directory permissions
find - find a file or directory
which - show the full path of a command
whereis - locate a command
locate - locate a command
history - display your most recent commands
man - read the online manual
ps - display your currently running processes
kill - kill a process
Viewing file contents or command output
cat - stream the contents of a file
more - view page by page
grep - search for lines that contain a string
sort - sort
ssh - run a command on another machine
slogin - login to another machine
scp - copy a file to/from another machine
Most Linux commands will display helpful information if you start the command with the -h or --help command-line argument. You can also get help for almost any Linux command by reading the man page for the command. You can read a man page with the command man <command>, where <command> is the command you need help for. The command man -k keyword searches the titles of all man pages for keyword. To print a man page, use the command nroff -man path_of_man_file | lp.
See Command Redirection.
See the online help at Viewing Linux File and Directory Permissions.
For help in starting, managing and stopping a process, see Process Management.
A good place to start would be the Linux Documentation Project. Many books about Linux are also available.
Follow these guidelines when creating a passphrase:
- Change your passphrase frequently--at the very least, once every six months.
- Do not use the same passphrase with different accounts.
- Do not write down your passphrase. If you need to store it somewhere, store it in an encrypted file or device.
- The longer the passphase, the less likely it will be cracked. A passphrase should be at least 10 to 12 characters long.
- A good technique for choosing a passphrase is to use the first letters of an obscure phrase.
- Another good method is to use an easy to remember sentence.
- Some of the characters of your passphrase should be upper- or lowercase letters, numbers and punctuation.
- Comply with the UIowa Enterprise Password Policy.
Insecure home directory permissions can allow people to look through, or even change and delete, your files and directories. If your home directory is readable by others, then anyone who can login to any workstation managed by the CLAS Linux Group may be able to see and possibly read any file or directory that you have stored in your account. If your home directory is writable by others, then anyone may also be able to create and possibly delete your files and directories. To give your home directory secure permissions, run this command:
chmod 0700 ~
The PATH environment variable is a list of directories separated by colons. When you type a command name without giving an explicit path (e.g., you type ls rather than /bin/ls), your shell searches each directory in the PATH in order, looking for an executable file by that name. The shell will run the first matching executable it finds. You can include the current working directory "." in the PATH. But if "." is the first directory in your PATH and you change to a publicly writable directory, such as /var/tmp, then if a file in the directory matches a command you type, you will execute the contents of that file - probably not what you intended to do!
If you need to restore a deleted file, see Restoring Files on the CLAS Linux Network.
Disk quota is a limit on the amount of disk space you can use. The default quota available for students, faculty and staff can be found on the Quota page.
You can check your quota with the quota -s -w command.
If you start to see errors such as "Disk Quota exceeded", then you are over your disk quota. There are two types of disk quota: hard and soft. If you are over your soft quota, you have one week to get your disk space usage below the soft quota. During this time, you will see warning messages telling you that your quota is exceeded. You can continue creating and modifying files until the one-week time period is expired, or until you go over your hard quota. Hard quota is absolute; once you have passed it, you can no longer save files. Once your soft quota time period has expired or your hard quota is exceeded, you will lose the contents of any file you work on!
You can reduce your disk usage by deleting unnecessary files. You can also compress or zip files that you don't use every day. If you are still over your quota after you have tried to reduce your disk usage, then you need to contact the CLAS Linux Group staff by opening a ticket in the Help Request Trouble Ticket System. If disk space is available on the system, and if you seem to be using your quota for valid educational or research work, your quota will be raised.
To print a text or PostScript file named <file_name> to the default printer, use the command lp <file_name>. To print the file to a printer named printer, use the command lp -dprinter <file_name>. To list the available printers available, use the command lpstat -a. To list the options for a printer, do lpoption -l -p printer. To print a file on only one side (no duplexing), do lp -dprinter -o Duplex=None <file_name>.
For a current list of printers, see the Printers.
To check a queue named <queue_name>, use the command lpstat -o <queue_name>.
There is no way to cancel a print job. If a job is stuck in a queue, open a ticket in the Help Request Trouble Ticket System.
For information about printing in color, see Color Printing.
Check the panel on the printer for any errors. If there is a paper jam, try to clear it. PLEASE BE CAREFUL WHEN CLEARING PAPER JAMS! Please do not damage the printers. If there is any other error on the panel, report it by opening a ticket in the Help Request Trouble Ticket System.
This can happen when printing from an application. Change the printer settings within the application, and try printing again.
For help setting up your Windows or Mac, contact Brian Bacher.
If you want to use an email service other than Hawkmail, you may be able to use an email client. All CLAS Linux workstations have alpine (a text-based mail application formerly known as pine) and Thunderbird (a graphical mail client). To start alpine, simply type alpine in a terminal window and press the Enter key. To start Thunderbird, click the icon on the toolbar at the top of your screen that is a picture of a blue bird carrying an envelope.
The CLAS Linux Group staff will not configure your Linux email client for you. If you have questions or need help configuring a Linux email client, contact your mail service provider.
Hawkmail - Hawkmail is the campus-wide email service provided by ITS
Use the two conversion programs dos2unix and unix2dos. The general format for using these commands is unix2dos unix_input_file converted_dos_output_file and dos2unix dos_input_file converted_unix_output_file.
Sometimes when you start Firefox, a box may pop up that warns you about a lock file. Whenever Firefox starts, it tries to create a file named lock in your Firefox directory ~/.mozilla/firefox/*.default. If you have another Firefox session running, or if a previous session ended abnormally, the lock file may still be there. Just delete it with the command rm ~/.mozilla/firefox/*.default/lock. You may also have to delete a .parentlock file with the command rm ~/.mozilla/firefox/*.default/.parentlock.
For help with publishing web pages, see Creating and Maintaining Web Pages.
To learn about restricting access to a web page, see How to Restrict Access to Web Pages.
For help with course support, see Course Support Help.