ULYSSIS documentation - User contributions [en]

Useful Linux Commands

2024-08-31T12:40:23Z

Timo: /* Getting help */

Once you've connected, you can use these commands to use the ULYSSIS shell.

First of all, whenever you need to type a longer command or filename, try the <code>TAB</code> key as it will try to complete the name of the command or file you are typing. Pressing <code>TAB</code> twice will show a list of possible completions.

A more extensive document on this can be found at https://info-ee.surrey.ac.uk/Teaching/Unix/.

==Basic file managment==

cd directoryname

Change directory. Works the same as under MS-DOS. cd without argument changes to your home directory (like My Documents in windows). Go to the parent directory with <code>cd ..</code>

ls

List the contents of the current directory. Many different formats are available, a common one is <code>ls -al</code>. To accomodate MS-DOS/Windows users, <code>dir</code> is an alias (synonym) for <code>ls -alF</code>, which gives output similar to the <code>dir</code> command in MS-DOS/Windows.

cp inputfile targetfile

Copy inputfile to targetfile. Additional arguments (e.g. -r or -v are explained in the man-page.)

mv inputfile targetfile

Move inputfile to targetfile. Additional arguments (e.g. -i or -v are explained in the man-page.) This is the way to rename a file. Note that you cannot use a construction like mv *.htm *.html to add an ``l'' to a bunch of files. A small shell script can provide a way to do this: <code>for i in *.htm; do mv i; done</code>

rm filename

Remove filename. Additional arguments (e.g. -r or -v are explained in the man-page.) Note: there is no undelete-alike function in most unices.

mkdir dirname

Creates a directory called dirname.

rmdir dirname

Removes an empty directory. Use rm -r to delete a directory and recursively everything in it. Add -f to disable any prompts (dangerous!).

==Getting help==

man command-name

Displays manual pages, if available. E.g. man ls. Use 'q' to exit. Relatives: apropos, help.

apropos word

Searches through headers of all man pages.

help command-name

Displays help about command-name. Only for internal bash-functions.

bash

The Bourne Again SHell. Widely used successor of sh, the Bourne shell. This is the program you're working under after you open a ssh-session (you don't have to start it to use it). Bash interprets your commands, and executes them. Tab-completion, * and ? expansions, etc are all bash functions. man bash will give you tons of info about it. Alternatives : tcsh, zsh, rc

==Text editors==

It's easier to use a text editor on a server, than editing your file locally and uploading that file.

nano

Probably the easiest text editor. Should be self-explanatory. The symbol ^ is used for the ctrl key and M- stands for alt.

vim

Probably the best text editor. Start editing by pressing i. Stop editing by pressing the escape key. Save and quit with :wq. Quit without saving with :q!.

==Utilities==

df

Displays info about the free diskspace on the system. df . will give info about the filesystem where the current directory resides. The output becomes a bit more readable with the -h switch.

du

Displays info about the diskusage in the current directory (and its subdirectories. A common parameter is -s , equivalent to -summarize , to summarize the disk-usage (without the per-subdir totals).

quota

Displays info about your diskusage, and your disk quota. Quota are limits on diskusage, imposed by the system administrator. The system will warn you if you exceed these limits.

ps

Displays info about processes. Various options possible, for example ps auxf gives info on all processes, including process owner, memory usage, and parent-child indication.

htop

Displays top CPU processes. Use it to see what gets most cpu power at the moment. Don't leave top open for a long time, since it eats cpu time itself. (quit with 'q').

[[Category:Shell]]

Useful Linux Commands

2024-08-31T12:37:33Z

Timo:

Once you've connected, you can use these commands to use the ULYSSIS shell.

First of all, whenever you need to type a longer command or filename, try the <code>TAB</code> key as it will try to complete the name of the command or file you are typing. Pressing <code>TAB</code> twice will show a list of possible completions.

A more extensive document on this can be found at https://info-ee.surrey.ac.uk/Teaching/Unix/.

==Basic file managment==

cd directoryname

Change directory. Works the same as under MS-DOS. cd without argument changes to your home directory (like My Documents in windows). Go to the parent directory with <code>cd ..</code>

ls

List the contents of the current directory. Many different formats are available, a common one is <code>ls -al</code>. To accomodate MS-DOS/Windows users, <code>dir</code> is an alias (synonym) for <code>ls -alF</code>, which gives output similar to the <code>dir</code> command in MS-DOS/Windows.

cp inputfile targetfile

Copy inputfile to targetfile. Additional arguments (e.g. -r or -v are explained in the man-page.)

mv inputfile targetfile

Move inputfile to targetfile. Additional arguments (e.g. -i or -v are explained in the man-page.) This is the way to rename a file. Note that you cannot use a construction like mv *.htm *.html to add an ``l'' to a bunch of files. A small shell script can provide a way to do this: <code>for i in *.htm; do mv i; done</code>

rm filename

Remove filename. Additional arguments (e.g. -r or -v are explained in the man-page.) Note: there is no undelete-alike function in most unices.

mkdir dirname

Creates a directory called dirname.

rmdir dirname

Removes an empty directory. Use rm -r to delete a directory and recursively everything in it. Add -f to disable any prompts (dangerous!).

==Getting help==

man command-name

Displays manual pages, if available. E.g. man ls. Use 'q' to exit. Relatives: apropos, help.

apropos word

Searches through headers of all man pages.

help command-name

Displays help about command-name. Only for internal bash-functions.

bash

The Bourne Again SHell. Widely used successor of sh, the Bourne shell. This is the program you're working under after you open a ssh-session (you don't have to start it to use it). Bash interprets your commands, and executes them. Tab-completion, * and ? expansions, etc are all bash functions. man bash will give you tons of info about it. Alternatives : tcsh, zsh, rc

==Text editors==

It's easier to use a text editor on a server, than editing your file locally and uploading that file.

nano

Probably the easiest text editor. Should be self-explanatory. The symbol ^ is used for the ctrl key and M- stands for alt.

joe

Another easy text editor. Press Ctrl+C to quit.

vim

Probably the best text editor. Start editing by pressing i. Stop editing by pressing the escape key. Save and quit with :wq. Quit without saving with :q!.

==Utilities==

df

Displays info about the free diskspace on the system. df . will give info about the filesystem where the current directory resides. The output becomes a bit more readable with the -h switch.

du

Displays info about the diskusage in the current directory (and its subdirectories. A common parameter is -s , equivalent to -summarize , to summarize the disk-usage (without the per-subdir totals).

quota

Displays info about your diskusage, and your disk quota. Quota are limits on diskusage, imposed by the system administrator. The system will warn you if you exceed these limits.

ps

Displays info about processes. Various options possible, for example ps auxf gives info on all processes, including process owner, memory usage, and parent-child indication.

htop

Displays top CPU processes. Use it to see what gets most cpu power at the moment. Don't leave top open for a long time, since it eats cpu time itself. (quit with 'q').

[[Category:Shell]]

Useful Linux Commands

2024-08-31T12:35:31Z

Timo:

Once you've connected, you can use these commands to use the ULYSSIS shell.

First of all, whenever you need to type a longer command or filename, try the <code>TAB</code> key as it will try to complete the name of the command or file you are typing. Pressing <code>TAB</code> twice will show a list of possible completions.

A more extensive document on this can be found at https://info-ee.surrey.ac.uk/Teaching/Unix/index.html.

==Basic file managment==

cd directoryname

Change directory. Works the same as under MS-DOS. cd without argument changes to your home directory (like My Documents in windows). Go to the parent directory with <code>cd ..</code>

ls

List the contents of the current directory. Many different formats are available, a common one is <code>ls -al</code>. To accomodate MS-DOS/Windows users, <code>dir</code> is an alias (synonym) for <code>ls -alF</code>, which gives output similar to the <code>dir</code> command in MS-DOS/Windows.

cp inputfile targetfile

Copy inputfile to targetfile. Additional arguments (e.g. -r or -v are explained in the man-page.)

mv inputfile targetfile

Move inputfile to targetfile. Additional arguments (e.g. -i or -v are explained in the man-page.) This is the way to rename a file. Note that you cannot use a construction like mv *.htm *.html to add an ``l'' to a bunch of files. A small shell script can provide a way to do this: <code>for i in *.htm; do mv i; done</code>

rm filename

Remove filename. Additional arguments (e.g. -r or -v are explained in the man-page.) Note: there is no undelete-alike function in most unices.

mkdir dirname

Creates a directory called dirname.

rmdir dirname

Removes an empty directory. Use rm -r to delete a directory and recursively everything in it. Add -f to disable any prompts (dangerous!).

==Getting help==

man command-name

Displays manual pages, if available. E.g. man ls. Use 'q' to exit. Relatives: apropos, help.

apropos word

Searches through headers of all man pages.

help command-name

Displays help about command-name. Only for internal bash-functions.

bash

The Bourne Again SHell. Widely used successor of sh, the Bourne shell. This is the program you're working under after you open a ssh-session (you don't have to start it to use it). Bash interprets your commands, and executes them. Tab-completion, * and ? expansions, etc are all bash functions. man bash will give you tons of info about it. Alternatives : tcsh, zsh, rc

==Text editors==

It's easier to use a text editor on a server, than editing your file locally and uploading that file.

nano

Probably the easiest text editor. Should be self-explanatory. The symbol ^ is used for the ctrl key and M- stands for alt.

joe

Another easy text editor. Press Ctrl+C to quit.

vim

Probably the best text editor. Start editing by pressing i. Stop editing by pressing the escape key. Save and quit with :wq. Quit without saving with :q!.

==Utilities==

df

Displays info about the free diskspace on the system. df . will give info about the filesystem where the current directory resides. The output becomes a bit more readable with the -h switch.

du

Displays info about the diskusage in the current directory (and its subdirectories. A common parameter is -s , equivalent to -summarize , to summarize the disk-usage (without the per-subdir totals).

quota

Displays info about your diskusage, and your disk quota. Quota are limits on diskusage, imposed by the system administrator. The system will warn you if you exceed these limits.

ps

Displays info about processes. Various options possible, for example ps auxf gives info on all processes, including process owner, memory usage, and parent-child indication.

htop

Displays top CPU processes. Use it to see what gets most cpu power at the moment. Don't leave top open for a long time, since it eats cpu time itself. (quit with 'q').

[[Category:Shell]]

Useful Linux Commands

2024-08-31T12:32:12Z

Timo: /* Text editors */

Once you've connected, you can use these commands to use the ULYSSIS shell.

First of all, whenever you need to type a longer command or filename, try the <code>TAB</code> key as it will try to complete the name of the command or file you are typing. Pressing <code>TAB</code> twice will show a list of possible completions.

A more extensive document on this can be found at http://info.ee.surrey.ac.uk/Teaching/Unix/.

==Basic file managment==

cd directoryname

Change directory. Works the same as under MS-DOS. cd without argument changes to your home directory (like My Documents in windows). Go to the parent directory with <code>cd ..</code>

ls

List the contents of the current directory. Many different formats are available, a common one is <code>ls -al</code>. To accomodate MS-DOS/Windows users, <code>dir</code> is an alias (synonym) for <code>ls -alF</code>, which gives output similar to the <code>dir</code> command in MS-DOS/Windows.

cp inputfile targetfile

Copy inputfile to targetfile. Additional arguments (e.g. -r or -v are explained in the man-page.)

mv inputfile targetfile

Move inputfile to targetfile. Additional arguments (e.g. -i or -v are explained in the man-page.) This is the way to rename a file. Note that you cannot use a construction like mv *.htm *.html to add an ``l'' to a bunch of files. A small shell script can provide a way to do this: <code>for i in *.htm; do mv i; done</code>

rm filename

Remove filename. Additional arguments (e.g. -r or -v are explained in the man-page.) Note: there is no undelete-alike function in most unices.

mkdir dirname

Creates a directory called dirname.

rmdir dirname

Removes an empty directory. Use rm -r to delete a directory and recursively everything in it. Add -f to disable any prompts (dangerous!).

==Getting help==

man command-name

Displays manual pages, if available. E.g. man ls. Use 'q' to exit. Relatives: apropos, help.

apropos word

Searches through headers of all man pages.

help command-name

Displays help about command-name. Only for internal bash-functions.

bash

The Bourne Again SHell. Widely used successor of sh, the Bourne shell. This is the program you're working under after you open a ssh-session (you don't have to start it to use it). Bash interprets your commands, and executes them. Tab-completion, * and ? expansions, etc are all bash functions. man bash will give you tons of info about it. Alternatives : tcsh, zsh, rc

==Text editors==

It's easier to use a text editor on a server, than editing your file locally and uploading that file.

nano

Probably the easiest text editor. Should be self-explanatory. The symbol ^ is used for the ctrl key and M- stands for alt.

joe

Another easy text editor. Press Ctrl+C to quit.

vim

Probably the best text editor. Start editing by pressing i. Stop editing by pressing the escape key. Save and quit with :wq. Quit without saving with :q!.

==Utilities==

df

Displays info about the free diskspace on the system. df . will give info about the filesystem where the current directory resides. The output becomes a bit more readable with the -h switch.

du

Displays info about the diskusage in the current directory (and its subdirectories. A common parameter is -s , equivalent to -summarize , to summarize the disk-usage (without the per-subdir totals).

quota

Displays info about your diskusage, and your disk quota. Quota are limits on diskusage, imposed by the system administrator. The system will warn you if you exceed these limits.

ps

Displays info about processes. Various options possible, for example ps auxf gives info on all processes, including process owner, memory usage, and parent-child indication.

htop

Displays top CPU processes. Use it to see what gets most cpu power at the moment. Don't leave top open for a long time, since it eats cpu time itself. (quit with 'q').

[[Category:Shell]]

Reducing disk usage

2024-04-29T12:31:09Z

Timo: /* Common sources of unnecessary disk usage */

__TOC__
This page discusses what happens when you use more disk space than has been allotted to your account (your quota) and how to reduce your disk usage. You may have been pointed here through an automatic email notification you are running over your quota, or through our support. This page is also useful if you want to reduce your disk usage even if you're not using more than your quota. You can check your current disk usage as well as your quota on https://ucc.ulyssis.org/quota.

This page first discusses what happens when you use more disk space than is available to your account type (so you therefore go over your quota). This is followed by a detailed manual on how to use the command line tool ''ncdu'' to look for the files and folders that may be causing trouble within your account. Finally, there's a list of examples of common causes for large disk space usage.

== What happens when I go over my quota? ==

If you are using more disk space than the allowed quota for your account type for more than seven consecutive days (the so-called grace period), you will no longer be able to write any additional files or extend existing files. You will probably no longer be able to edit websites on your account or it might even stop working outright. If you haven't configured a forwarder for your <code>''username''@ulyssis.org</code> email address, you will lose emails sent to this address. The grace period of seven days is intended for you to have time to reduce your disk space. You will receive an email every day reminding you that you are using too much disk space. In order to prevent impact on other users in cases where disk usage within an account suddenly and substantially surges, an additional quota slightly higher than your normal quota is imposed, independent of any grace period.

== Identifying which files & folders use the most disk space ==
It is not always easy to immediately identify what is taking up space on your account. Sadly, there are no dependable cross-platform tools to help with this. Instead, we will be using the command line tool ''ncdu'', which runs directly on one of our shell servers. You do not need to be proficient with command line interfaces in order to use this tool, the step-by-step manual below will guide you through the process. However, should you get stuck, do not hesitate to contact us at <code>ulyssis@ulyssis.org</code>.

* Connect through SSH to one of the shell servers: https://docs.ulyssis.org/Accessing_shell_servers_over_SSH
* Type in <code>ncdu</code> and press enter. You will then see that <code>ncdu</code> is scanning your account.
* Once <code>ncdu</code> has finished scanning, it will display which files or folders located directly in your home directory are using the most disk space. When the filename starts with <code>/</code> it is a folder. The results are ordered by size, so it makes most sense to start with the top items.
* You can select different files/folders using the '''up and down arrow keys''', navigate the directory structure using either the '''enter and backspace''' keys or the '''left and right''' arrows to move in and out of folders, quit ncdu by pressing '''q''' and delete a file or folder with '''d'''. Be careful to not delete files you still need as you will need to contact us in order to restore them from a backup.
* You can check your progress on https://ucc.ulyssis.org/quota. The percentage and values displayed are always current and accurate, there is no delay.[[File:Disk usage ncdu.png|thumb|760x760px]]

=== Common sources of unnecessary disk usage ===

* Your ULYSSIS mailbox: Depending on your account settings, your ''@ulyssis.org'' email account may be used as a forwarder or an inbox. When set to ''Inbox'' on https://ucc.ulyssis.org/mail, email will be saved to the ''Maildir'' folder within your account. A substantial amount of email, especially with large attachments, may grow to quite a significant size. You can verify the contents of your mailbox easily by logging in on https://webmail.ulyssis.org using your ULYSSIS account credentials. You can then remove those emails that are no longer useful, and don't forget to empty the trash. To remove the entire mailbox, you can simply remove the Maildir folder from your account (using ncdu, [[Accessing your files#Using Cyberduck|Cyberduck]], or another tool). To empty the trash manually, you can remove the ''Maildir/.Trash'' folder. If you no longer wish to use you mailbox, don't forget to change the configuration on https://ucc.ulyssis.org/mail to forward your messages, since you may receive relevant information about your account through this address.
* Old websites: if you have older websites on your account that you are no longer using, it might be worth removing them in their entirety. If the deleted website uses a database (this will always be the case if your using WordPress, MediaWiki or another popular CMS), then you should also delete those through our control panel: https://ucc.ulyssis.org (either the MySQL or PostgreSQL sections). If this website had an associated (sub)domain, please send us an email to have it removed. Also keep in mind that old websites may pose a security risk, so it's never good to leave them lying about.
* Unused images: in the case of many CMSes (WordPress, Drupal, ...), removing an image from a post will not delete it. For example, in the case of WordPress it will still be available through the Media Library. You can easily find these [https://wordpress.com/support/media/2/#unattached-files unattached files]. In order to reclaim the disk space used by the image, you will have to [https://wordpress.com/support/trash/#permanently-deleting-an-upload delete] it there as well. Similarly, MediaWiki offers a list of ''unused files'' as a special page available in the list of ''Special Pages''. Keep in mind that WordPress or MediaWiki might not always be aware an image or other file is used when it has not been added through its interfaces or through a third party plugin.
* Large images: images and especially pictures are often several MBs in size and often have a large resolution. While this is great for editing and printing, such large sizes are not all that useful for inclusion in a webpage. They can make your site load slower and use more disk space without a significant increase in quality. You should therefore consider resizing images before uploading them or installing a plugin, module or extension that reduces their size on upload. However, make sure to watch out for plugins that keep the original image around as this will not reduce but increase your disk usage. For a tutorial on how to resize images, you can take a look at https://wordpress.com/support/media/image-optimization/. This tutorial is geared towards WordPress, but is also applicable in general. If you are using MediaWiki, we have written a plugin that reduces the size of various types of files. You can find more details on [[Setting up MediaWiki#Extensions|Setting up MediaWiki - Extensions]].
* Backups: ULYSSIS makes daily backups of all account data, including databases, and keeps them for at least a month. It is therefore not necessary to make automated backups of your own, for example with plugins such as [https://nl.wordpress.org/plugins/updraftplus/ Updraft] for WordPress. Although it is a good practice to make backups whenever you are making large changes to your site, it is not necessary to keep them after you have verified that your site works correctly.
* Anything missing on this list? Feel free to contact us on <code>ulyssis@ulyssis.org</code> with your suggestions.
[[Category:Files]]
[[Category:Account]]

Reducing disk usage

2024-04-29T12:24:37Z

Timo: /* Identifying which files & folders use the most disk space */ typo

__TOC__
This page discusses what happens when you use more disk space than has been allotted to your account (your quota) and how to reduce your disk usage. You may have been pointed here through an automatic email notification you are running over your quota, or through our support. This page is also useful if you want to reduce your disk usage even if you're not using more than your quota. You can check your current disk usage as well as your quota on https://ucc.ulyssis.org/quota.

This page first discusses what happens when you use more disk space than is available to your account type (so you therefore go over your quota). This is followed by a detailed manual on how to use the command line tool ''ncdu'' to look for the files and folders that may be causing trouble within your account. Finally, there's a list of examples of common causes for large disk space usage.

== What happens when I go over my quota? ==

If you are using more disk space than the allowed quota for your account type for more than seven consecutive days (the so-called grace period), you will no longer be able to write any additional files or extend existing files. You will probably no longer be able to edit websites on your account or it might even stop working outright. If you haven't configured a forwarder for your <code>''username''@ulyssis.org</code> email address, you will lose emails sent to this address. The grace period of seven days is intended for you to have time to reduce your disk space. You will receive an email every day reminding you that you are using too much disk space. In order to prevent impact on other users in cases where disk usage within an account suddenly and substantially surges, an additional quota slightly higher than your normal quota is imposed, independent of any grace period.

== Identifying which files & folders use the most disk space ==
It is not always easy to immediately identify what is taking up space on your account. Sadly, there are no dependable cross-platform tools to help with this. Instead, we will be using the command line tool ''ncdu'', which runs directly on one of our shell servers. You do not need to be proficient with command line interfaces in order to use this tool, the step-by-step manual below will guide you through the process. However, should you get stuck, do not hesitate to contact us at <code>ulyssis@ulyssis.org</code>.

* Connect through SSH to one of the shell servers: https://docs.ulyssis.org/Accessing_shell_servers_over_SSH
* Type in <code>ncdu</code> and press enter. You will then see that <code>ncdu</code> is scanning your account.
* Once <code>ncdu</code> has finished scanning, it will display which files or folders located directly in your home directory are using the most disk space. When the filename starts with <code>/</code> it is a folder. The results are ordered by size, so it makes most sense to start with the top items.
* You can select different files/folders using the '''up and down arrow keys''', navigate the directory structure using either the '''enter and backspace''' keys or the '''left and right''' arrows to move in and out of folders, quit ncdu by pressing '''q''' and delete a file or folder with '''d'''. Be careful to not delete files you still need as you will need to contact us in order to restore them from a backup.
* You can check your progress on https://ucc.ulyssis.org/quota. The percentage and values displayed are always current and accurate, there is no delay.[[File:Disk usage ncdu.png|thumb|760x760px]]

=== Common sources of unnecessary disk usage ===

* Your ULYSSIS mailbox: Depending on your account settings, your ''@ulyssis.org'' email account may be used as a forwarder or an inbox. When set to ''Inbox'' on https://ucc.ulyssis.org/mail, email will be saved to the ''Maildir'' folder within your account. A substantial amount of email, especially with large attachments, may grow to quite a significant size. You can verify the contents of your mailbox easily by logging in on https://webmail.ulyssis.org using your ULYSSIS account credentials. You can then remove those emails that are no longer useful, and don't forget to empty the trash. To remove the entire mailbox, you can simply remove the Maildir folder from your account (using ncdu, Cyberduck, or another tool). To empty the trash manually, you can remove the ''Maildir/.Trash'' folder. If you no longer wish to use you mailbox, don't forget to change the configuration on https://ucc.ulyssis.org/mail to forward your messages, since you may receive relevant information about your account through this address.
* Old websites: if you have older websites on your account that you are no longer using, it might be worth removing them in their entirety. If the deleted website uses a database (this will always be the case if your using WordPress, MediaWiki or another popular CMS), then you should also delete those through our control panel: https://ucc.ulyssis.org (either the MySQL or PostgreSQL sections). If this website had an associated (sub)domain, please send us an email to have it removed. Also keep in mind that old websites may pose a security risk, so it's never good to leave them lying about.
* Unused images: in the case of many CMSes (WordPress, Drupal, ...), removing an image from a post will not delete it. For example, in the case of WordPress it will still be available through the Media Library. You can easily find these [https://wordpress.com/support/media/2/#unattached-files unattached files]. In order to reclaim the disk space used by the image, you will have to [https://wordpress.com/support/trash/#permanently-deleting-an-upload delete] it there as well. Similarly, MediaWiki offers a list of ''unused files'' as a special page available in the list of ''Special Pages''. Keep in mind that WordPress or MediaWiki might not always be aware an image or other file is used when it has not been added through its interfaces or through a third party plugin.
* Large images: images and especially pictures are often several MBs in size and often have a large resolution. While this is great for editing and printing, such large sizes are not all that useful for inclusion in a webpage. They can make your site load slower and use more disk space without a significant increase in quality. You should therefore consider resizing images before uploading them or installing a plugin, module or extension that reduces their size on upload. However, make sure to watch out for plugins that keep the original image around as this will not reduce but increase your disk usage. For a tutorial on how to resize images, you can take a look at https://wordpress.com/support/media/image-optimization/. This tutorial is geared towards WordPress, but is also applicable in general. If you are using MediaWiki, we have written a plugin that reduces the size of various types of files. You can find more details on [[Setting up MediaWiki#Extensions|Setting up MediaWiki - Extensions]].
* Backups: ULYSSIS makes daily backups of all account data, including databases, and keeps them for at least a month. It is therefore not necessary to make automated backups of your own, for example with plugins such as [https://nl.wordpress.org/plugins/updraftplus/ Updraft] for WordPress. Although it is a good practice to make backups whenever you are making large changes to your site, it is not necessary to keep them after you have verified that your site works correctly.
* Anything missing on this list? Feel free to contact us on <code>ulyssis@ulyssis.org</code> with your suggestions.
[[Category:Files]]
[[Category:Account]]

ULYSSIS public IRC

2024-04-11T15:24:31Z

Timo:

ULYSSIS hosts its own IRC network. IRC stands for Internet Relay Chat, [https://en.wikipedia.org/wiki/Internet_Relay_Chat IRC on wikipedia]. It is a chat protocol that mainly focuses on group chat, but also allows for private chat.

For any support questions, you are free to contact us via email on ulyssis@ulyssis.org, but if your questions are of a less sensitive nature and could benefit from a back-and-forth, it could be useful to contact us on IRC. Do keep in mind that you may have to wait until someone notices your question, which may take a while. If you don't have a question and just want to hang out in our chat, feel free to join!

Keep in mind that our IRC network has been a social space for several generations, so you will find alumni and students from different walks of life there, not just ULYSSIS members and users.

==Web IRC client==
If you won't regularly use our IRC or if you just want to check it out, you can use our web IRC client. You can find it at [https://webirc.ulyssis.org/ webirc.ulyssis.org]. Remember to leave your web IRC browser tab open while you wait for a response.

==IRC network details==

Below are specific instructions for some clients, but if you are already familiar with IRC, here are the details you need to connect to our server. We highly recommend using SSL.

Server: irc.ulyssis.org
Port: 6668 (SSL)
Channel: #ulyssis

If <code>irc.ulyssis.org</code> is down, you can also try the other server in the same network, hosted at <code>irc2.ulyssis.org</code>. Both are connected to each other and you can use them interchangeably. It is advised to add it as a fallback in your IRC client.

==IRC clients==
To use IRC, you'll need an IRC client. We advise the terminal based [https://irssi.org/ irssi] or [https://weechat.org/ weechat] for Linux and [https://hexchat.github.io/ hexchat] or [https://www.mirc.com/ mIRC] for Windows, but there are a lot of other free options.

You can only receive messages over IRC while you're connected. Therefore, we advise you to run irssi or weechat in either a screen or a tmux session. With a ULYSSIS account, you can run screen or tmux on our shellservers, as they keep running 24/7 you can use them to keep track of your conversations.
Screen and tmux are similar programs. Screen has been around for longer and is more tested, while tmux is more modern with new features and being easier to use for beginners.

===Using irssi on our shell servers===
====Connect to the shellserver====
Use the ssh command in your Linux or OS X terminal, or use PuTTY to connect on windows.
Extensive information on how to do so can be found on [[Accessing shell servers over SSH]].

====Start irssi in a screen====
*When on the shellserver, enter <code>screen -U</code> to start a screen session, or <code>tmux</code> to start a tmux session.
*Enter <code>irssi</code> to start irssi
*Connect to the IRC server: <code>/connect -ssl irc.ulyssis.org 6668</code>
*Connect to the public channel: <code>/join #ulyssis</code>

====Screen usage====
*To exit the screen: press Ctrl-A and press D ('detach') to return to the shellserver.
*To reconnect: enter <code>screen -r</code> or <code>screen -DR</code> (the latter will create a new screen if it wasn't already made).

====Tmux usage====
*To exit the tmux session: press Ctrl-B and press D ('detach') to return to the shellserver.
*To reconnect: enter <code>tmux attach</code>

====Help, I can't reconnect to my session!====
*Check if you are on the right shell server and didn't make a typing error.
*If everything is correct, your screen may have been stopped by a crash or a reboot of our shellserver. You can check the [http://status.ulyssis.org status] section of our website for more information about possible downtimes.
*Make sure you use the right program (<code>screen</code> if you started a screen session and <code>tmux</code> if you started a tmux session)

==Using ZNC==
Alternatively, if you don't like using terminal-based clients, or just want to run your client locally, you can connect with our [https://znc.ulyssis.org/ ZNC server]. However, to use it, you'll need a ULYSSIS account. ZNC connects to our IRC server in your place (fill in the details at the beginning of this article). You can then connect to ZNC with a client of your choice, and it will send you the history you've missed while you were offline.

Log in to our ZNC server. In your settings, create a new network. Fill in the basic details (server name, nickname, set <code>BindHost</code> to <code>0.0.0.0</code>). In the server field, fill in <code>irc.ulyssis.org +6668</code>. Add <code>#ulyssis</code> as a channel. You may want to increase the buffer count. Then save at the bottom of the page.

In your IRC client, connect to the server <code>znc.ulyssis.org</code> on port 6666 (with SSL) and set <code>username/network:password</code> as password to the server. Replace <code>username</code> with your ULYSSIS username, <code>network</code> with the name of the network in your znc settings, and <code>password</code> with your ULYSSIS password.

==Using Bitlbee==

With [https://www.bitlbee.org/main.php/news.r.html Bitlbee], you can connect to other services as if they were an IRC server. It is available at <code>bitlbee.ulyssis.org</code> on ports 7000 and 7001 (SSL). For documentation on how to use Bitlbee, we refer to the manual on its website. This service is only reachable from within the ULYSSIS and KU Leuven networks.

[[Category:Shell]]
[[Category:ULYSSIS Public Services]]