Table of Contents


General

  1. What is Grex?

    Grex is a public-access Unix system providing free shell accounts and a computer conferencing community. It is based out of the United States. It is cooperatively owned and operated, and is supported entirely by user donations and volunteers.

  2. What does the name Grex mean?

    Grex is not an acronym. It is a Latin word meaning flock. It is the root of a number of familiar English words such as aggregate, congregate, and gregarious.

  3. What can I do on this system?

    Grex provides all of the following services for free.

    • Interactive Unix shell access, and access to the standard suite of Unix software including shells, tools and document preparation software.
    • An interactive software development environment supporting many languages, compilers, editors, interpreters and tools.
    • A number of software packages of mathematical, scientific, and statistical processing.
    • Internet email using "mail", "mutt", "alpine" or "mh"
    • Browse the web in text mode using "links", "w3m" or "lynx"
    • Access to IRC
    • Access to USENET
    • Access to SSH, scp, sftp, and ftp to connect to other systems and services
    • Free web site hosting
    • On-line games, including "Nethack"
    • Electronic conferencing using "Backtalk" or "Fronttalk"
    • Multichannel real-time chat using "party"

    Please note that you must be a validated user to use software anything related to the network.

    And there are a few things you can only do if you are a member (who has made a donation and sent ID). These are

    • Vote in Grex elections.
    • Serve on the board of Cyberspace Communications.
  4. What operating system is Grex running?

    Grex is currently running a nearly stock version of OpenBSD.

    For the first 13 years of it's life, Grex ran on second-hand Sun computers, using Sun's proprietary version of Unix. However, Grex now runs on standard server hardware based on the Intel 386 instruction set.

    There are a lot of details about Grex's configuration available in the Grex staff notes on the web. Follow this link to more information about Grex's Hardware and software.


Conferencing

  1. What is "computer conferencing?"

    A computer conference is an area set aside for discussion on some general topic, such as computers, politics, or gardening. In such an area, people can read what other people have posted, and can introduce new subtopics or add responses to existing ones. On many systems, conferences are called "forums". Grex has many conferences. For a complete list, see https://grex.org/cgi-bin/backtalk/pistachio/conflist.

  2. How can I participate in Grex's conferences?

    Grex's conferences are accessible by a text-based terminal interface or by the World Wide Web. To access the text-based interface, SSH into Grex and run the "bbs" command. (This command is run automatically every time you log in if you choose the "bbs shell" after you validate your account.) World Wide Web access is provided by Grex's "Backtalk" conferencing software. Please see https://grex.org/cgi-bin/backtalk for details on using Backtalk.


Governance

  1. How is Grex governed?

    Cyberspace Communications functions as an online democracy, with policies set by its users. The Co-op Conference is open to all users and provides a forum for discussing policy issues. The Board of Directors, elected by the members, is the formal governing body and uses consensus in the Co-op Conference as its primary guide for making decisions. Any member of Grex who can attend the monthly meetings, held in Ann Arbor, Michigan, is eligible to run for the Board of Directors. In addition, any member can call a binding vote by the membership on any policy issue. The Articles of Incorporation and Bylaws can be viewed online.

  2. How can I participate in Grex governance?

    Any user can have a voice in Grex governance by joining the Co-op conference and participating in the discussions there. If you wish to be eligible to vote in Grex elections and to run for the Board of Directors, you can become a Grex member. Membership dues are US$2/month or US$18/year. To find out how to make membership payments, please see http://grex.org/member.xhtml. Membership donations are Grex's primary source of financing.

  3. Can I pay for membership by credit card?

    Yes!


How do I ... ?

  1. How do I change my name, my shell, my mail forwarding or my password?

    You can change any of these properties of your account with the "change" command. If you are using a menu or if you are at a bbs (Ok) prompt, type "!change" If you are in lynx, type "!" (an exclamation point) to get to a shell prompt first. At a shell prompt, type "change" and follow the menu-based instructions.

  2. How do I change my login ID?

    You can't change it. Instead, you have to create a new account with the login ID that you wish. Once you have done that, you can copy the files that you need from your old account to your new one. When you no longer need your old account, you can ask to have it deleted by sending a request from your old account to help@grex.org.

  3. How do I set up a web page?

    There is a completely separate FAQ for all questions related to the Grex web server. Please see http://grex.org/wwwfaq.xhtml.

  4. How do I access IRC?

    If you are an unvalidated user, you cannot access IRC. We strongly urge you to get validated! Send email to porters@grex.org to get started! You must have a Grex user name in order to be validated. Please see http://grex.org/newuser/index.xhtml for instructions.

    If you are a validated user, you can access IRC through a number of clients we have installed including the venerable ircII, the well-known irssi, sirc and several others.

  5. Grex does not allow the running of bots or bouncers such as psybnc or eggdrop. They will be killed if found running.

  6. How do I chat with others?

    Grex has six ways of chatting:

    • 'party' is a chat program that many people can run at once.
    • 'write' sends text to the other person's screen one line at a time.
    • 'chat' is like 'write' but it sends one character at a time.
    • 'tel' is like 'write' but it sends only one line and then stops.
    • 'talk' splits the screen in half, so both people can type at once.
    • 'ytalk' is like talk but can accommodate more than two people.
  7. How do I get out of vi?

    vi (pronounced vee-eye) is a powerful text editor, but it has a steep learning curve at first. You can usually tell that you are in vi when you have a vertical line of squiggles (tildes) on the left of your screen. If you are trapped in vi, remember to type the escape key and then :q! (colon-q-exclamation point) followed by a return. The "ee" and "pico" editors are much friendlier for less experienced users.

  8. How do I access Usenet news?

    There are a number of Usenet reader programs on Grex, including slrn, tin, trn and nn. You can also access Usenet via one of the text web browsers installed on Grex, such as w3m, links or lynx. Just connect to http://groups.google.com/.

  9. How do I run X11 programs?

    The easiest way is to login to Grex using SSH, which will likely set your DISPLAY environment variable and X authority files automatically. Then, just run the graphical program in question. Alternately, you may have to specify these settings by hand; check the X11 documentation for more details.

    Note, however, that using X from Grex is likely to be painfully slow, and also uses a lot of resources on Grex itself. We ask that, in general, you refrain from using X programs.

  10. How do I restore a lost file from a backup

    We can't do that. We just don't have time. Grex makes nightly backups, but the purpose of these backups is to protect the system from disaster. Unfortunately, there is not enough time to honor requests from individual users to restore files. Grex is not a good place to keep any file that you cannot afford to lose. If you have an important file on Grex, it is your responsibility to keep a backup of it on your own computer.

  11. How do I get a list of Unix commands?

    There are so many Unix commands that we recommend that users who are not familiar with Unix use the "menu" command to explore Grex. The most common commands are available there. If you really want a list, then run the Grex command "listcommands" to print a list of most Unix commands on Grex. (Built-in shell commands are not included). This will take a long time to run.

  12. How do I use Unix commands?

    The Unix operating system is amazingly powerful and flexible, with thousands of commands. Unix can be a challenge to get started with, but if you are interested in learning Unix, Grex is a good place to start, since we do give you access to almost all commands.

    For online introductions to basic Unix commands and editors such as emacs and vi usage, consult Google and do searches for things like, Unix tutorial or vi tutor.

    Online reference information about most commands can be called up via the "man" command. For example, for information about the date command, type:

    man date

    The book Unix for the Impatient is excellent, though slightly dated.

  13. How do I access Web mail?

    You can try with one of the textual browsers installed on Grex, but most web-based mail services expect graphical browsers with more functionality. However, you can use some webmail servers (for instance, GMail) by configuring one of the mail programs already installed on Grex (for instance, mutt or alpine) to pull mail via POP3 or IMAP from a remote server and to send outgoing mail through a remote server.


Accounts and Passwords

  1. I can't remember my password. What do I do?

    Contact the Grex staff. Send mail from another site if you have access to email at another site. Send messages about access problems to help@grex.org. Remember to specify which account is the one you lost the password for.

    You can also log in to Grex as "trouble" without a password, which will send a message to the staff. Be sure to provide a postal address, an email address, or a local telephone number, so that the staff can contact you in return.

  2. I have a Grex account. Why do I get "No such loginid?"

    This means that your account has been deleted. Accounts on Grex are deleted if no one logs in for more than 3 months. There is not enough room on Grex to keep old unused accounts. To avoid losing your account, you should log in every month or two. Accessing your web page, or having your mail get forwarded does not count, but conferencing over the web using your account and password in Backtalk does count as logging in for this purpose.

    If your account has been deleted, it usually cannot be recovered or restored. Please feel free to recreate the account.

  3. I don't want to use my account anymore. How do I get it deleted?

    If you don't want to wait until your account expires, you have to log in one last time and send a message to help@grex.org from the account that you want deleted. In your message, ask for it to be deleted.

  4. When I enter my password, why don't I see anything?

    Grex does not display your password as you type it. This is to keep it secret from anybody who might be looking over your shoulder. Type your password anyway. Even though you don't see it, Grex will register it and, if you typed it correctly, you will be logged in.


Email

  1. How do I get Grex to forward my mail to another site?

    Put the address to which you would like your Grex email forwarded to in a file called ".forward" in your home directory.

    If you don't know how to do that, you can use the "change" command. Just type "change" at a shell prompt or "!change" at any other prompt. This will invoke a menu that allows you to change common setting for your account, including the mail forwarding option.

  2. I set up .forward myself. Why doesn't it work?

    Probably because it is not world readable. .forward files must be world readable in order to be valid on Grex. If you are looking for a way to forward your mail to an anonymous place, you need to find an anonymous remailer system. Grex doesn't do this. To make your .forward file world readable, change to your home directory (type: cd) and then issue this command:

    chmod 644 .forward

    Your home directory must also be world accessible; type:

    chmod 755 .

    or use 711 instead of 755 if you don't want other people to be able to scan your directory.

  3. How can I hide my forwarding address?

    You can't. Grex does not wish to provide anonymous remailing services. You may wish to make use of one of the various anonymous remailers available on the Internet; use your favorite web search engine to find one.

  4. How do I read mail with Thunderbird or Outlook?

    Configure your local client to connect to Grex via SSL encrypted IMAP and SMTP; enter your grex login name and password where prompted.

    Please note, we support the IMAP protocol, but not POP3.

  5. My mailbox is getting heavily spammed. What can I do?

    Spam (unwanted mail) is unfortunately very common on the internet, and there's little anyone can do about it.

    Grex has installed SpamAssassin to help you cut down on the noise. This reduces but does not eliminate spam.

  6. Why is mail that I send to Grex getting rejected?

    This usually happens when the sending site is not configured properly. Problems in mail configuration can often lead to mail that has an invalid return address. Grex's mail system tries very hard to detect and reject invalid sending addresses, in order to reduce the amount of spam on Grex. If your mail looks like spam, then Grex will reject it. If you think this is happening to your legitimate mail, send a rejected copy of it to help@grex.org, and be sure to include all of the mail headers. Ordinarily, the additional surrounding text and context of the forwarded email should be enough to convince the mailer that the email is legitimate.

    Other common reasons for mail to Grex to be rejected are that it may be too large or your mailbox may have grown too large.

  7. Can I configure my mail program to save outgoing mail?

    This feature is turned off on Grex by default, because lots of new users were accumulating vast files of old mail without ever knowing that they were doing it. You're quite welcome to configure this feature, as long as you keep an eye on your disk usage so that you don't exceed Grex's 100 megabyte limit for your account.

    To configure your mail client, consult its documentation. For alpine, go into the configuration screen and look for the setting for "default-fcc". Set it to "saved-mail" or whatever name you would like to use. You need to use quotation marks around the file name.

  8. Can I send attachments?

    Yes. You must first transfer the file you wish to attach to Grex, and then attach it when composing your email message. If you don't need the file on Grex after you've sent it, please remember to delete the file after you are done. Also, please keep attachments to a reasonable size so as not to overwhelm our service.

  9. How can I view an attachment file named myfile.doc?

    Any file that ends with ".doc" is probably a Microsoft Word file. There is no way to view such a file on Grex. You will have to download that file to a computer that has Microsoft Word or some other word processor that can import such files.

  10. How can I set the "From" header in pine for my outgoing mail?

    In Pine on Grex, you can't set the "From:" field. This is disabled because there were too many problems with people setting invalid addresses, which caused their outgoing mail to bounce to the postmaster whenever it was undeliverable.

  11. How do I set up a mailing list here?

    You can't. We're sorry, but this is not permitted. You can only forward mail to a single site elsewhere on the internet. Mailing lists are too resource intensive for Grex to support. You may wish to try using an advertising-based free mailing list service. Both Google Groups and Yahoo Groups offer free mailing lists with lots of features.

  12. Is it OK to collect my mail by SCP, SFTP or FTP?

    Yes, but you must do it correctly.

    It is risky to attempt to transfer your mail spool file off of Grex. You risk losing some or all of your collected mail, because the sftp, scp and FTP daemons does not participate in the locking scheme used by the mail delivery programs. In addition, your account may appear to be abandoned because file transfers do not update the date of last login. This could result in loss of your account if it is the only way you use Grex.

    Instead, we recommend connecting to Grex and running a mail client program. These all do participate in the locking mechanism for the mail spool. Collect all of your mail into a file in your home directory, and then log out. You may now safely fetch that file, but please remember to delete it once it has been safely transferred.

  13. Why can't I get procmail to work?

    The most likely reason is that you have not told procmail how to find your mail spool file. To find your spool file, type

    echo $MAIL

    Procmail will work if you make this one of the first lines of the .procmailrc file:

    MAIL=PATH-TO-YOUR-INBOX

    For example, the first line of a .procmailrc file used by member John Remmers (remmers) would be:

    MAIL=/var/mail/remmers
  14. Can I set up an autoresponder to answer my mail while I am away for a while?

    Yes. Try the vacation program. Type vacation to run it.


Privacy, Encryption, and Security

  1. My personal information should be private. Why is it shown?

    When you look up your own user information, you can always see it, even if it is set up so that nobody else on the system can see it. To see what other people see, ask for the info about "youraccount@grex.org" instead of just "youraccount".

  2. How can I keep private the place I'm logged on from?

    This is considered public information on Grex. The only way to hide it is not to log on.

  3. I am receiving unwanted chat requests. What can I do?

    You can adjust the chat settings for your account with the "change" command. To run it, type "change" at a shell prompt, or "!change" from a menu or from bbs. Then choose "W) Write settings" and follow the menus from there. You can: turn off all chat requests, accept all chat requests, or select which users can and cannot chat with you.

  4. How can I view my friend's files?

    Grex is a very open system, so directories are open to the public unless the owner decides to make them private. Email, however, is automatically saved in private files that the world cannot see.

    To permit a file so that it can be seen by others, type

    chmod a+r file-name

    To permit a directory, type

    chmod a+rx dir-name

    To hide a file or directory, type

    chmod ou-rx file-or-dir-name

    If you hide your home directory completely, neither mail forwarding nor web hosting will be available to you. You may make your directory accessible without allowing it to be scanned. This is how:

    chmod 711 dir-name
  5. Can I run PGP on Grex to protect my email messages from being seen by others?

    Yes. PGP is available on Grex, but be aware that will probably offer you the protection you seek on our service. In order to be effective, PGP must be installed on your own computer, not on Grex, which you should not consider secure. Encrypting or decrypting a message on Grex would mean that the message would have to travel over an insecure network before encryption or after decryption, and this is not the way to protect your message. Even if you connect to Grex using SSH, there is still a huge risk that Grex itself will be compromised.

    In order to install PGP on your home computer, North American users should go to the MIT PGP Distribution Site at http://web.mit.edu/network/pgp.html, and all other users should use the international PGP home page at http://www.pgpi.org/.

  6. Do you provide secure shell?

    Yes, we do. Secure shell (ssh) is a good way to connect because your session is encrypted, so that passwords cannot be intercepted by sniffers. In fact, we have removed telnet access in favor of SSH in October 2011 due to these security concerns.

  7. Do you allow Grex to be used as a proxy using SSH?

    Sorry, no this type of connection is disallowed by our firewall settings, so it won't work.


Programming

  1. How do I compile a program?

    To compile a C program named foo.c, type gcc foo.c -o foo This compiles foo.c and creates an executable program named foo. To run it, type ./foo Likewise, to compile a C++ program named foo.cpp, type g++ foo.cpp -o foo Please check with the Grex staff before compiling programs you bring in from the net. Most of the useful programs are already installed here, and many others will not run on Grex, but compiling them on Grex wastes a lot of bandwidth and cpu time — resources that Grex is short on.

  2. I compiled my program. Why won't the system run it?

    Usually this is because the program is not on your path. Unlike a DOS or Windows system, on Unix the current directory is not automatically placed on your path. So if you compile a program named foo, you cannot run it by just typing "foo". You need either to place the executable somewhere on your path, or to precede its name with ./ (dot-slash) so you would type "./foo".

  3. Can I have a copy of Grex's write/chat/tel programs?

    Yes, you can find out more about write/chat/tel, including availability, on this web page: http://unixpapa.com/write.html.

  4. Can I have a copy of Grex's party program?

    Yes, you can find out more about party, including availability, on this web page: http://unixpapa.com/party.html.

  5. Please install Java?

    Java is installed on Grex.


Miscellaneous

  1. Why does my browser say "Can't find application" when I click on the "SSH In" link?

    You need to configure your browser to find your SSH application program. The exact instructions for doing this vary widely depending upon both your operating system and your browser. Select the SSH application that came with your system, or one you downloaded from the internet. For more details about SSH applications, see the Grex SSH Information page at http://grex.org/ssh.xhtml.

  2. When I try to SSH to Grex, it hangs. Why can't I connect?

    There are several things that can go wrong.

    • You don't have DNS working properly. In this case you can connect to Grex by using its IP address. See below.
    • You are accessing the net via a firewall which blocks SSH. In this case you need to contact your security administrator for the LAN which you are accessing the net from, and ask if there is a way to SSH through the firewall.
    • Your SSH client is not working properly. You would not be able to SSH to any other site, either. Have you tried any? Try connecting with SSH to arbornet.org and see if you get a login prompt.
    • Grex is down. This happens occasionally. You can usually tell if Grex is down by trying to access the web site. Try reloading to eliminate the possibility of a cached page. This won't be a good test if your connection uses a caching proxy server.
    • If it is none of the above, send mail to The Grex Staff and explain everything you tried, and also please specify the IP address and the GMT time that your attempt failed. If you can provide the results of a ping or traceroute from your end, that may prove to be helpful, too.
  3. Can I do a ping or traceroute from Grex?

    These tools are not available on Grex. Vandals were using them to attack other sites. This is a ludicrous thing to do from Grex, because Grex is so tiny that its CPU and net connection become overloaded long before any other system would even begin to notice that it was being attacked. But people were doing it anyway, and hurting Grex. Regrettably, the actions of a few thoughtless people has forced Grex to disable these potentially valuable network analysis tools.

    You may be able to use a remote traceroute server on the web. See http://www.traceroute.org/.

  4. What is Grex's IP address?

    At the time this answer was last updated, the IP address of Grex was 162.202.67.158, but IP addresses may change at any time. In general we have little control over changes to our IP address. You should always use the hostname, because if the IP address does change, the DNS (Domain/Name Service) lookup of the hostname should produce the new IP address. If you unsure if a problem is due to DNS, you can test to see if you can connect using our IP address. However, if you can, it is strongly recommended that you resolve the problem you are having with DNS, so that you do not have to rely on inherently unreliable IP addresses.

  5. Why does the "who" command show numeric IP addresses for some users?

    That is because this information is stored in a file (utmp) which only permits 16 characters of storage for this information. If the IP address exceeds 16 characters when converted to text form, then it is stored (and reported) only in its numeric form. This affects other commands besides the "who" command, such as the "finger" and "last" commands.

  6. How much disk space can I use and how can I determine how much I am using?

    The disk quota on grex is 100 megabytes, enforced by the 'quota' system. You can find out how much disk space you are using (in kilobytes) by running the following command in your home directory:

    du -sk

    The number that comes back is the number of kilobytes of disk you are using. If you are using more than 100000, please remove files.

    The command

    quota

    will show your quota and usage on the current file system. The command

    quota -v

    will show your quota and usage on all the file systems you have "write" access.

    If you are thinking of putting something big in your account, please talk to the Grex staff (help@grex.org) first. There aren't many good reasons to put big things in your Grex account: Grex doesn't allow multimedia files on its web pages (not even image files), and most of the useful programs that will actually run on Grex are already installed on Grex. So please talk to the staff first.

    If you exceed the 100 megabyte disk quota or have multimedia files, big downloaded program packages, or vandal tools, in your account, a member of the Grex staff will delete the files and quite likely lock your account. The Grex staff spent way too much time policing this and was usually quite crabby about the whole topic. So the current Grex computer has automated disk quotas, which will notify you when you go over quota and prevent your creating new files if you stay over quota.

  7. Why doesn't my arrow key work, so I can edit previous commands in sh?

    This is because Grex is running a real sh, and that is a feature not supported by sh. What some Unix systems call sh is actually bash, an enhanced version of the sh shell which does this. If you would like to use bash instead, you should change your shell on Grex to bash. You can do that by running the change command.

  8. Why can't I edit previous commands in tcsh, ksh, or bash? They are supposed to support it.

    Bash, ksh and tcsh do support previous line editing. It may not be working the way you expect because a different default editing mode is in use. To change the default editing mode to the style of emacs or vi, the command you must use depends upon your shell. For ksh and bash, use one of the following commands:

    set -o emacs
    set -o vi

    The equivalents in tcsh are:

    bindkey -e
    bindkey -v

    After that, you should be able to edit your command line in a way that is familiar to you. If you prefer to preserve this setting so you don't have to execute it every time you log in, then place it in .profile (ksh and bash) or .login (tcsh).

  9. Why does the last line of each page of text disappear from the screen before I can read it?

    This happens when Grex doesn't know how many rows of text are on your screen. The easiest way to set this correctly is to run the "resize" program on Grex. It will set things up for you.

  10. Why do the bottom lines stay on the screen in the editor while the rest scroll normally?

    Same problem. Wrong number of lines in the setting. See solution above.

  11. Why doesn't "screen" work when I disconnect from Grex?

    Grex runs a special daemon that kills all user processes when a user logs out. This prevents users from running servers or robots of any kind. It also prevents them from using the reconnect feature of screen (although the other features work fine). The reason for this policy is to prevent users from consuming our limited resources while not logged in.

  12. I found a huge core file in my account. What should I do?

    Nothing really. This is a file that gets created if a program fails (crashes). It is intended to help the programmer find whatever bug caused the failure. If not renamed, these files will be deleted automatically in a day or two. You can delete it if you wish. By the way, a core file usually doesn't take up as much space on the disk as it appears to, because it is "sparse" (full of empty space).

  13. How does the system decide where to put my home directory?

    Grex uses a hierarchical arrangement of home directories to keep the directory sizes from growing too large and thus becoming inefficient. So, on Grex, home directories are always located by a path of this form:

    /x/y/z/username

    The x is the disk letter, the y is the first letter of the username, and the z is the second letter of the username. Currently we have two disks that user accounts occupy, /a and /c (/b was not available). The choice of disk is determined when your account is created. This choice is switched back and forth manually by the staff to keep the available disk space balanced.

    The environment variable $HOME should always be set to the full path of your home directory. The ~ symbol may also be used as a shorthand for your home directory, as long as your shell supports it. (The Bourne Shell does not.)

  14. Where can I get a self-contained multi-user chat program for my linux box?

    You might want to try out Grex's party program. See the Party Question in this FAQ.

  15. How can I get colors in the output from "ls"?

    Color listings are available with many terminal types, but whether or not they show up depends on which terminal emulator you're using. See http://grex.org/ssh.xhtml for more information on SSH programs. You also need to turn on color listing. This involves two steps. You will need to run gdircolors for you shell. If your shell is a sh-like shell (sh, bash, ksh), you will run the following command: eval `gdircolors -b` otherwise, if your shell is a csh like shell (csh, tcsh) you will run the following command: eval `gdircolors -c` Then, if you use ls with the --color=auto option, it will use colors. You can add the following alias to your .profile file of startup commands (for bash-type shells, or your .login file for csh-type shells): alias ls='/usr/local/bin/gls --color=auto' to always get color listings when your terminal emulator can support it.

  16. I know something about Unix. How can I help the Grex staff?

    We are always delighted to have new volunteers One of the things that Grex needs most urgently is more people to answer "help" requests. It is recommended that you check out the helpers conference.

    Also you should read the Grex Staff Notes.