Frequently Asked Questions - all

Connecting to the Windows Terminal Server from Mac OS

1. On your Mac, open the "App Store" application and install the "Microsoft Remote Desktop" application.
2. Launch Microsoft Remote Desktop.
3. From the main menu bar, select File -> New
4. Complete the pop-up connection dialog as described below:
   1. Name the connection with a descriptor of your choice.
   2. The "PC name" will be: csnt-ts.unl.edu.
   3. A gateway is not required.
   4. Use your School of Computing (SoC) credentials. Please Note how the login is prefixed with "CS.UNL.EDU\".
   5. If "Native" Resolution does not work, select one that is suitable to your device.
   6. Uncheck "Start session in full screen" if you would rather have the windows desktop appear in a window.
   7. Uncheck "Use all monitors" if you have a multi-monitor Mac and would like the windows desktop to be on one screen.
5. Close the dialog by clicking on the "x" on the upper left on the dialog.
6. The new connection will now appear on the main "Microsoft Remote Desktop" pane.
7. Double click on the created connection to establish a remote connection to the terminal server.

A sample new connection dialog is shown below.

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Common problem with setting up home pages

• Your home directory and public_html directory must have world execute permissions.
• Your html documents must be given world read access
• Any images enclosed should have a path relative to your public_html directory. The image load will fail if you specify a full path to the image
• To point to another file in your public_html directory, use a hypertext link of the following form
• Tail the /var/log/apache2/error_log (The tail command shows any new lines added to a file) while you try to access your page to see if there are any errors.

   > tail -f /var/log/apache2/error_log 

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Printing from Mac via SMB

List of Printers

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How to I check my printer quota and balances?

Your remaining printer quota along with the printers you have access to, is displayed on the main page of the School of Computing (SoC) Account Management Utility (AMU) page at https://cse.unl.edu/account.

Additional printer quota can be purchased from the system administration offices in Avery 27C. The current cost is $6.00 per 100 pages. The cost is charged to your NCard charge account, so you will need to present your NCard at time of purchase.

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Compilers and Interpreters available on cse.unl.edu

Compilers

gcc	GNU CcCompiler
g++	GNU C++ compiler
javac	Java compiler
gfortran	GNU Fortran compiler
clisp	Common Lisp
alisp	Allegro Common Lisp

Interpreters

perl	Perl command line scripting language
php	Command line and web scripting language
ruby	Command line and web scripting language
pyton	Command line scripting language

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Basic Unix Commands

Note on systax used in document:

items in [] are optional

items in {} can be repeated 0 or more times.

fn = filename (possible with wildcards)

dir = directory name

File System:

cat fn {fn}

concatenate, can be used to display a file.

more fn {fn}

displays file(s) one screenful, at a time. At MORE prompt enter: space bar - for next screenful <cr> - for next line, q - to quit more command.

cp fn1 fn2

copy file - fn1 to fn2, fn1 remains.

mv fn1 fn2

move (rename) file - fn1 to fn2, fn1 no longer exists.

rm fn

remove (delete) file.

lpr -Pprinter_name fn

print a file, printer_name = ps16 or ps17.

ls [fn]

list files in current directory option filename is usually used to display files matching wildcards. (ie. ls *.s will list all assembly language source files.)

ls -lgRa

Recursive listing of all files within all subdirectories. Longest, most descriptive format.

cd [dir]

change working directory, ``home directory" if not specified. cd .. will backup one level in the directory structure.

pwd

print working directory path.

mkdir dir

make a new directory, giving it the name dir (within the current directory)

rmdir dir

remove (delete) the directory named dir (the directory must be empty)

file fn

Tries to determine what kind of information is in a file by consulting the file system index and by reading the file itself.

du

Prints a summary of total space occupied by all files in a hierarchy.

sort fn

Sorts ASCII files line-by-line.

chmod

Change file permissions. See the man pages for a complete description of settings. Use this command to determine whether files can be readable by other people.

find . -name filename

In it's most simple form find will display all files in this and any subdirectories which name matches filename. See the man page for find for a complete description of this command. Find can be use to find files matching name patters, dates, owners, sizes, etc. and to perform action on matched files.

gzip fn

Use this to compress files not needed immediately to conserve disk space. A ``.gz" will be appended to the filename.

gzip -d

Uncompresses files with ``.Z" at end of filename.

head {-n} fn

Prints first n lines of a text file. If no number is specified, the default is 10.

tail {-n} fn

Prints last n lines of a text file. If no number is specified, the default is 10.

tail {-n} fn

Prints last n lines of a text file. If no number is specified, the default is 10.

grep string fn

Print occurrences of string in file

Remote Connection:

ssh remote_host

Launch a secure shell to the remote host specified.

Communication:

finger

list users currently on the system.

who

list users currently on the system.

w

what, similar to who but includes what they are doing.

pine

Email message utility.

pine username

will send Email to username.

talk username

allows two users to have an interactive conversation over the computer.

write username

allows a user to put a message on another users screen.

mesg n

Makes it so other users cannot interrupt you with talk requests, and write messages.

Help:

man command

manual, returns the manual for the given command from the UNIX on-line manual. If you cannot find a man page for a command, there may be one in a directory that isn't in your MANPATH. Your MANPATH is setup in the .login file and a command's man page is usually in a man directory off the same parent directory as the command. For example, if the command is located in /usr/local/bin, its man page is probably in /usr/local/man.

man -k keyword

display manual headings containing the word keyword.

Miscellaneous:

alias name def

Assigns ``def'' to the alias ``name''. Usually found in the .cshrc file. For example ``alias dir ls -la''.

clear

Clears screen.

history

List history of commands used.

!!

re-execute the last command entered.

!x

re-execute the last command that started with the given letter, eg !c will re-execute the last command that began with the letter c.

jobs -l

list all currently stopped or background jobs with job numbers and process ID's.

kill [-signal] %jobnumber

kill the given job number. Use the "jobs" command to show running jobs. You might need to kill a job to logout if you have accidentally put a job into the background or stopped a job. Use -TERM or -KILL singlas to force quite jobs.

kill PID

kill the given Process. refer the "ps" command to find running processes. Use -TERM or -KILL singlas to force quite jobs.

ps -fa

list all your current processes. See the man page for a full description.

<control>C

kill the current process - the one in the  foreground

<control>Z

suspend foreground process.

bg

put a suspended job in the background.

fg

put a suspended or background job in the foreground.

date

display time and date.

To find out about more commands, click  here.

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How do I access a command line session on the SoC Unix server?

For certain classes you will be required to access a command line session on the School of Computing (SoC) Unix server: cse.unl.edu.

Connecting to cse.unl.edu from a Windows personal laptop

Search for "putty win32" using a search engine (Google/DuckDuckGo/Bing). Download and install the PuTTY application on your computer. Then follow the steps in the next section.

Connecting to cse.unl.edu from a Lab Windows machine

1. Launch PuTTY - there should be a desktop icon for PuTTY, or look for it in the start menu.
2. In the "PuTTY Configuration" dialog that pops up, enter "cse.unl.edu" in the Host Name field, click on "SSH" as the Connection type, and click the "Open" button.
3. If this is the first time you're connecting to cse.unl.edu, there will be a Security Alert popup asking you if you want to accept the server's host key. Click on "Yes."
4. Login with your SoC login user name and password when prompted. If you do not know your SoC login or password, visit the SoC Account Management Utility page, https://cse.unl.edu/account.

If you are prompted for a Verification code: after entering your password, examine the login user name you supplied to the login: prompt. Login user names containing a digit at the end, e.g. fred4, are not valid user names for SoC systems. If you supplied the wrong user name you will need to start a new PuTTY SSH session using the correct login user name.

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How do I access my CSE home directory from a Windows PC on campus?

If you are working on campus from a computer lab or on your personal laptop, you might wish to map your home directory from the school server directly onto your laptop, so as to not have to transfer files up and down.

The instructions given are for Windows 10:

1. Launch File Explorer, there are many way to do this: From the start menu, select the Documents item to open the "File Explorer".
   
   Or you can select the "File Explorer" from the Windows System menu.
   
   If you have a "My Computer" or "My PC" icon on the desktop, you can double click on the icon to launch File Explorer.
2. In the File Explorer window, click on the Computer tab on the top of the window to display a ribbon, then click the Map network drive icon if shown:
   
   or right-click on "My PC" to show the 'map network drive' option.  
   
   This will open a "Map Network Drive" dialog.
   
3. In the dialog, type in "\\cse-smb1.unl.edu\login_id" without the quotes and where login_id would be your School of Computing CSE login ID. For example if your CSE login was csmith, your folder path would be: \\cse-smb1.unl.edu\csmith
   
4. Check on the "Connect using different credentials" checkbox, uncheck "re-connect at sign-in" and click on the "Finish" button.
5. When you are asked to enter your network credentials, you will need to login with your SoC credentials. Your user name must be provided as "CS.UNL.EDU\username". As in the example above, if your CSE username (login) was csmith, the user name value would be: CS.UNL.EDU\csmith
   
6. Provide your CSE password and Click "OK". You should see your home directory from the departmental server mapped as a drive in the File Explorer window.

If you are not offered the option to enter credentials or Windows returns an error indicating it cannot communicate or find the cse-smb1.unl.edu server, ensure you are connect to the eduroam network, and the eduroam network is private network. You can verify that you have the required Windows client service enabled using these instructions on Windows SAMBA settings.

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Visitor Registration for University Wireless Network

The wireless network on campus is managed by Information Technology Services. Visitors to the Univerisity of Nebraska needing wi-fi access can register for 14-day, limited wi-fi access by visiting the ITS page on NU-Guest setup. Please note that the NU-Guest wi-fi network is restricted in services that can be accessed and services such as SSH will not be accessible when connected to the NU-Guest wi-fi network.

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Message Size Limits (Legacy users)

The maximum message size is 10MB for outgoing email messages sent through SMTP on cse.unl.edu and cse-mail.unl.edu.  This limit applies to the entire size of the message, which includes the message body, headers, and any attachments.

If you absolutely need to send a message that is larger than 10MB, you can send a request via email to support@cse.unl.edu to have the message size limit temporarily increased on the server. However, large files should not normally be sent as attachments in email messages. Instead, please consider using OneDrive to share files.

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I forgot my CSE password or login

If you have forgot your password, visit the School of Computing (SoC) Account Management Utility (AMU) page at https://cse.unl.edu/reset_password. Enter your email account, for students this would be your @huskers.unl.edu email. An email with a link to reset your password will be sent to your email.

To recover your CSE login id, visit the AMU login recovery page at https://cse.unl.edu/lost_login and enter your email. This will send an email to you containing your CSE systems login id.

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How do I check my disk quota?

If you are having issues saving file to your home directory (Unix) or your Z: Drive (Windows), you might have exceeded your disk quota.

Quotas are used to limit the amount of disk space used and the total number of files of each user. Disk space used is measured in blocks, where 1 block equals 1024 bytes(1KB).

There are two values (called limits) — a soft limit and a hard limit — for both the disk space used quota and the number of files quota. You can continue to increase your usage over the soft limit until you either reach the hard limit or the established time limit (usually a week). Once the hard limit has been reached, all further attempts at file creation will fail with an error message.

The simplest way to view your disk quota is to visit the School of Computing Account Management Utility (AMU) page at https://cse.unl.edu/account. After login, the AMU page shows various details about your account including your disk quota and usage.

To check your disk quota under Unix, use the  command "quota -v" at the Unix command shell prompt.

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Editing a File on Unix with vi - Basic Commands.

What is  vi?

The default editor that comes with the UNIX operating system is called  vi ( visual editor). [Alternate editors for UNIX environments include  pico and  emacs, a product of GNU.]

The UNIX  vi editor is a full screen editor and has two modes of operation:

1. Command mode commands which cause action to be taken on the file, and
2. Insert mode in which entered text is inserted into the file.

In the command mode, every character typed is a command that does something to the text file being edited; a character typed in the command mode may even cause the  vi editor to enter the insert mode. In the insert mode, every character typed is added to the text in the file; pressing the  <Esc> ( Escape) key turns off the Insert mode.

While there are a number of  vi commands, just a handful of these is usually sufficient for beginning  vi users. To assist such users, this Web page contains a sampling of basic  vi commands. The most basic and useful commands are marked with an asterisk ( * or star) in the tables below. With practice, these commands should become automatic.

NOTE: Both UNIX and  vi are  case-sensitive. Be sure not to use a capital letter in place of a lowercase letter; the results will not be what you expect.

To Get Into and Out Of  vi

To Start  vi

To use  vi on a file, type in  vi filename. If the file named  filename exists, then the first page (or screen) of the file will be displayed; if the file does not exist, then an empty file and screen are created into which you may enter text.

To Exit  vi

Usually the new or modified file is saved when you leave  vi. However, it is also possible to quit  vi without saving the file.

Note: The cursor moves to bottom of screen whenever a colon ( :) is typed. This type of command is completed by hitting the  <Return> (or  <Enter>) key.

Moving the Cursor

Unlike many of the PC and MacIntosh editors,  the mouse does not move the cursor within the  vi editor screen (or window). You must use the the key commands listed below. On some UNIX platforms, the arrow keys may be used as well; however, since  vi was designed with the Qwerty keyboard (containing no arrow keys) in mind, the arrow keys sometimes produce strange effects in  vi and should be avoided.

If you go back and forth between a PC environment and a UNIX environment, you may find that this dissimilarity in methods for cursor movement is the most frustrating difference between the two.

In the table below, the symbol  ^ before a letter means that the  <Ctrl> key should be held down while the letter key is pressed.

Screen Manipulation

The following commands allow the  vi editor screen (or window) to move up or down several lines and to be refreshed.

Adding, Changing, and Deleting Text

Unlike PC editors, you cannot replace or delete text by highlighting it with the mouse. Instead use the commands in the following tables.

Perhaps the most important command is the one that allows you to back up and  undo your last action. Unfortunately, this command acts like a toggle, undoing and redoing your most recent action. You cannot go back more than one step.

The main purpose of an editor is to create, add, or modify text for a file.

Inserting or Adding Text

The following commands allow you to insert and add text. Each of these commands puts the  vi editor into insert mode; thus, the  <Esc> key must be pressed to terminate the entry of text and to put the  vi editor back into command mode.

Changing Text

The following commands allow you to modify text.

Deleting Text

The following commands allow you to delete text.

Cutting and Pasting Text

The following commands allow you to copy and paste text.

Other Commands

Searching Text

A common occurrence in text editing is to replace one word or phase by another. To locate instances of particular sets of characters (or strings), use the following commands.

Determining Line Numbers

Being able to determine the line number of the current line or the total number of lines in the file being edited is sometimes useful.

Saving and Reading Files

These commands permit you to input and output files other than the named file with which you are currently working.

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