Eaten by a Grue's questions -ubuntu

Eaten by a Grue

Asked: 2024-09-05 23:08:11 +0800 CST

New default user group "users"

5

Apparently the group "users" has existed in the past but AFAIK went largely unused. Now in Ubuntu 24 new users created with adduser are added to it by default:

info: Adding new user `example' to supplemental / extra groups `users' ...
info: Adding user `example' to group `users' ...

I don't recall ever seeing this in the past. What is the purpose of the group "users" and for what reason has default the behaviour of adduser changed?

Eaten by a Grue

Asked: 2021-09-29 10:54:35 +0800 CST

rdiff-backup tempdir appears to be empty

1

I recently had a problem with restoring an incremental snapshot using rdiff-backup where my main drive ran out of space. After setting --tempdir as discussed here, the problem went away and while restoring I can see bytes diminishing with df -h on the specified path's device.

Oddly, the actual path I set appears to be completely empty. Neither ls nor du indicates that there is anything at all occupying the path in question.

Is anyone here familiar enough with the inner workings of rdiff-backup to shed some light on where the temp files are actually being written? And how is it that they seem to be invisible?

Eaten by a Grue

Asked: 2021-05-30 04:34:33 +0800 CST

Stuck on 20.04.1 LTS

1

I have two machines that are more or less exactly the same. Both were deployed as 20.04 LTS and run mirrors of the same software. Recently while performing system maintenance I noticed that they are running slightly different versions:

Machine A: Ubuntu 20.04.1 LTS (GNU/Linux 5.4.0-29-generic x86_64)
Machine B: Ubuntu 20.04.2 LTS (GNU/Linux 5.4.0-70-generic x86_64)

/etc/apt/sources.list is identical on both machines. Running apt-get update; apt-get upgrade does not help.

What could be causing this?

Eaten by a Grue

Asked: 2020-05-19 06:55:38 +0800 CST

Cannot increase MySQL table_open_cache in Ubuntu 20.04

2

I've read both of these related questions and still stuck:

MySQL table_open_cache is set to 8000 in /etc/mysql/mysql.conf.d/mysqld.cnf and this value is not defined in any of the other loaded cnf files:

table_open_cache = 8000

Also, in /lib/systemd/system/mysql.service I have the default entry:

LimitNOFILE=10000

When I query variables from the cli I still get this:

mysql> show variables like 'table_open_cache';
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| table_open_cache | 4745  |
+------------------+-------+

Also there's this:

$ ulimit -n
1024

Which is confusing because if the open files limit was being restricted by system shouldn't I be capped at 1024 instead of 4745? I don't understand where 4745 is even coming from.

Can someone please explain what's going on here? Is this a MySQL configuration problem or a limit being imposed by the operating system? I just migrated from Ubuntu 16.04 with nearly identical config and this was not a problem before.

OS is Ubuntu 20.04. MySQL version is 8.0.20.

Eaten by a Grue

Asked: 2018-10-07 13:53:22 +0800 CST

Where are Ubuntu 18 network shares configured?

3

I have a local server running Ubuntu 18.04.1 which was recently upgraded from Ubuntu 15 where I had a few shares configured manually via Samba in /etc/samba/smb.conf like:

[myshare]
    path = /home/user
    writeable = yes
    valid users = root, user

This has continued to work just fine since the upgrade but today I noticed if I right-click on a directory in Gnome I get a dialog window with a tab called "Local Network Share" that looks like this:

I enabled it and now it's showing up on my LAN as another share. My question is, where is this configured? Is it using Samba as well or some other service? I took a look at smb.conf where the other shares are configured but its not there.

Eaten by a Grue

Asked: 2018-06-11 06:33:02 +0800 CST

undefined parameters in /etc/postfix/master.cf

5

The default master.cf file in a fresh installation of Ubuntu 18 seems to contain some undefined parameters:

Under both the submission block and the smtps block:

  -o smtpd_client_restrictions=$mua_client_restrictions
  -o smtpd_helo_restrictions=$mua_helo_restrictions
  -o smtpd_sender_restrictions=$mua_sender_restrictions

What's going on here? Is this a bug? Or is the package maintainer expecting us to define these ourselves?

This came up for me yesterday when I got these warnings while installing a new package:

postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_sender_restrictions
postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_client_restrictions
postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_helo_restrictions
postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_sender_restrictions
postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_client_restrictions
postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_helo_restrictions

Eaten by a Grue

Asked: 2017-01-21 07:06:39 +0800 CST

MySQL update overwrites collation

1

I recently added a new collation to MySQL as outlined here for the purpose of including a dash - character in fulltext searches. It worked fine but a couple of days later my changes were overwritten by the apt.systemd.daily Unattended-Upgrade routine (which btw, I had no idea existed).

My question: Is there an upgrade-proof way to modify MySQL collation / charsets? I understand some system files are not meant to be altered, but typically there would be an appropriate user configuration file where those changes can be applied. Since I followed the official guidelines, I am surprised that these are files which would be replaced by an automatic system process.

UPDATE: Just to be 100% clear I'm talking about edits made to the following two files (which are referenced in the article I linked above):

/usr/share/mysql/charsets/Index.xml
/usr/share/mysql/charsets/latin1.xml

Eaten by a Grue

Asked: 2016-07-29 12:24:39 +0800 CST

Permission denied using "man"

3

For some reason an Ubuntu server (14.04.4 LTS) I'm working on will not allow "man" to be run by regular user. Example:

man ls
man: can't change directory to '/root': Permission denied
man: command exited with status 255: (cd /root && LESS=-ix8RmPm Manual page ls(1) ?ltline %lt?L/%L.:byte %bB?s/%s..?e (END):?pB %pB\%.. (press h for help or q to quit)$PM Manual page ls(1) ?ltline %lt?L/%L.:byte %bB?s/%s..?e (END):?pB %pB\%.. (press h for help or q to quit)$ MAN_PN=ls(1) pager -s)

How might this have happened and more importantly how can I fix it?

UPDATE:

Seems this only occurs after I su user where "user" is a non privileged user. Workaround is to su -l user but I still don't understand why man would become a privileged command without the login flag.

Eaten by a Grue

Asked: 2016-06-16 00:49:50 +0800 CST

Wrongly named variables in mysqld.cnf (Ubuntu 16.04)

2

Recently installed Ubuntu 16.04 and found that the default configuration file for MySQL has a few wrongly named variables, i.e. system variables whose name has changed over versions.

In the file /etc/mysql/mysql.conf.d/mysqld.cnf there are the following lines:

table_cache            = 64
log_slow_queries = /var/log/mysql/mysql-slow.log
log-queries-not-using-indexes

The current version of MySQL in use requires these to be named:

table_open_cache
slow_query_log_file
log_queries_not_using_indexes

Respectively. Is this a bug in the Ubuntu release or a problem somewhere else? My question is:

Who is to be blamed for this and should a bug report be filed?

At the very least, perhaps some frustrated individual will find this question and get answers.

Eaten by a Grue

Asked: 2016-04-18 17:30:02 +0800 CST

Block port on one network address

0

I'd like to block a series of ports (mailserver) for all the network addresses on my server except one. I've got a server running Ubuntu 14.04.4 and configured with 2 ipv4 addresses per Linode's Static IP configuration tutorial. /etc/network/interfaces looks something like this:

auto eth0 eth0:0

iface eth0 inet static
    address 93.184.216.34/24
    gateway 93.184.216.1

# This is a second public IP address
iface eth0:0 inet static
    address 93.184.216.35/24

I need first address to run the mailserver but the second needs to drop all incoming traffic except webserver ports (80,443).

I'm having a bit of difficulty here since every search result I get seems to relate to blocking specific IP addresses from connecting - instead of blocking all IP address from connecting to a specific server iface / ip address.

Eaten by a Grue

Asked: 2015-09-21 09:37:47 +0800 CST

How can I find all the possible cron settings?

0

I recently discovered that cron (at least on Ubuntu 14+) supports a setting called CONTENT_TYPE where I can specify the content type for emails like:

CONTENT_TYPE="text/html; charset=utf-8"

On another non-Ubuntu server I use the version does not support this. I looked at every man page I could find to no avail. Is there a way to find out all of the supported settings for a given version of cron?

Eaten by a Grue

Asked: 2015-08-26 15:32:11 +0800 CST

Error updating mailman

3

Received this error message today doing apt-get upgrade

Setting up mailman (1:2.1.16-2ubuntu0.1) ...
Looking for enabled languages (this may take some time) ... done.
Removing unmodified files from /etc/mailman/eu  done.
Directory /etc/mailman/eu not empty, not removed.
Removing unmodified files from /etc/mailman/no  done.
Directory /etc/mailman/no not empty, not removed.
Removing unmodified files from /etc/mailman/he  done.
Directory /etc/mailman/he not empty, not removed.
Removing unmodified files from /etc/mailman/tr  done.
Directory /etc/mailman/tr not empty, not removed.
Removing unmodified files from /etc/mailman/pt_BR  done.
Directory /etc/mailman/pt_BR not empty, not removed.
Removing unmodified files from /etc/mailman/lt  done.
Directory /etc/mailman/lt not empty, not removed.
Removing unmodified files from /etc/mailman/sk  done.
Directory /etc/mailman/sk not empty, not removed.
Removing unmodified files from /etc/mailman/nl  done.
Directory /etc/mailman/nl not empty, not removed.
Removing unmodified files from /etc/mailman/et  done.
Directory /etc/mailman/et not empty, not removed.
Removing unmodified files from /etc/mailman/hr  done.
Directory /etc/mailman/hr not empty, not removed.
Removing unmodified files from /etc/mailman/de  done.
Directory /etc/mailman/de not empty, not removed.
Removing unmodified files from /etc/mailman/it  done.
Directory /etc/mailman/it not empty, not removed.
Removing unmodified files from /etc/mailman/zh_CN  done.
Directory /etc/mailman/zh_CN not empty, not removed.
Removing unmodified files from /etc/mailman/fr  done.
Directory /etc/mailman/fr not empty, not removed.
Removing unmodified files from /etc/mailman/sr  done.
Directory /etc/mailman/sr not empty, not removed.
Removing unmodified files from /etc/mailman/zh_TW  done.
Directory /etc/mailman/zh_TW not empty, not removed.
Removing unmodified files from /etc/mailman/ru  done.
Directory /etc/mailman/ru not empty, not removed.
Removing unmodified files from /etc/mailman/ja  done.
Directory /etc/mailman/ja not empty, not removed.
Removing unmodified files from /etc/mailman/cs  done.
Directory /etc/mailman/cs not empty, not removed.
Removing unmodified files from /etc/mailman/fi  done.
Directory /etc/mailman/fi not empty, not removed.
Removing unmodified files from /etc/mailman/el  done.
Directory /etc/mailman/el not empty, not removed.
Removing unmodified files from /etc/mailman/ca  done.
Directory /etc/mailman/ca not empty, not removed.
Removing unmodified files from /etc/mailman/ar  done.
Directory /etc/mailman/ar not empty, not removed.
Removing unmodified files from /etc/mailman/sl  done.
Directory /etc/mailman/sl not empty, not removed.
Removing unmodified files from /etc/mailman/pt  done.
Directory /etc/mailman/pt not empty, not removed.
Removing unmodified files from /etc/mailman/hu  done.
Directory /etc/mailman/hu not empty, not removed.
Removing unmodified files from /etc/mailman/es  done.
Directory /etc/mailman/es not empty, not removed.
Removing unmodified files from /etc/mailman/vi  done.
Directory /etc/mailman/vi not empty, not removed.
Removing unmodified files from /etc/mailman/ko  done.
Directory /etc/mailman/ko not empty, not removed.
Removing unmodified files from /etc/mailman/ro  done.
Directory /etc/mailman/ro not empty, not removed.
Removing unmodified files from /etc/mailman/gl  done.
Directory /etc/mailman/gl not empty, not removed.
Removing unmodified files from /etc/mailman/fa  done.
Directory /etc/mailman/fa not empty, not removed.
Removing unmodified files from /etc/mailman/da  done.
Directory /etc/mailman/da not empty, not removed.
Removing unmodified files from /etc/mailman/pl  done.
Directory /etc/mailman/pl not empty, not removed.
Removing unmodified files from /etc/mailman/ia  done.
Directory /etc/mailman/ia not empty, not removed.
Removing unmodified files from /etc/mailman/uk  done.
Directory /etc/mailman/uk not empty, not removed.
Removing unmodified files from /etc/mailman/sv  done.
Directory /etc/mailman/sv not empty, not removed.
Removing unmodified files from /etc/mailman/ast  done.
Directory /etc/mailman/ast not empty, not removed.
Installing site language en ............................................ done.
Downgrade detected, from version 0x20112f1 to version 0x20110f0
This is probably not safe.
Exiting.
dpkg: error processing package mailman (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 mailman
E: Sub-process /usr/bin/dpkg returned an error code (1)

I am running Ubuntu 14.04.3. My question is:

What would cause this?

Update: Per @Ravan's comment below I was able to fix the problem by

cd /var/lib/dpkg/info/
rm mailman*
apt-get clean all
apt-get update
apt-get upgrade

Although things are better now, I still don't have an answer to what would have caused this.

Eaten by a Grue

Asked: 2014-07-06 19:21:40 +0800 CST

keep iptables up to date

0

I've installed iptables-persistent (Ubuntu 14.04) with the impression that it automatically saves iptables on shutdown but that appears not to be the case? It seem to load saved rules at startup but unless I save them beforehand (service iptables-persistent save) they are loaded from an older ruleset.

Am I doing something wrong or is this the way the iptables-persistent package is meant to behave?

Is there a recommended method of keeping /etc/iptables/rules.v4 current so that it is always up to date in the event of an unexpected power outage, or in case I restart and forget to save the rules?

I've considered using a cron script but really not sure if I am simply misunderstanding or have something configured wrong.

Eaten by a Grue

Asked: 2014-07-06 17:28:00 +0800 CST

iptables-persistent not uninstalling

2

I'm running Ubuntu 14.04 and I simply want to uninstall iptables-persistent to test something.

sudo apt-get remove --auto-remove iptables-persistent

... but it's still there. I tried again and got the message:

Package 'iptables-persistent' is not installed, so not removed

But it isn't removed. I rebooted and still am able to run

/etc/init.d/iptables-persistent save

and /etc/init.d/iptables-persistent is still there. What am I missing? Shouldn't that file be gone after removing it as I did?

Eaten by a Grue

Asked: 2014-07-02 11:56:59 +0800 CST

opendkim-genkey txt record in Ubuntu 14.04

1

After upgrading to Ubuntu 14.04 and generating keyfile using opendkim-genkey I've noticed the txt file is broken like:

myselector._domainkey   IN  TXT ( "v=DKIM1; k=rsa; "

"p=dhijvfhbdifg54t345t3456h3457" )  ; ----- DKIM key myselector for mydomain.com

I can only assume this is ok, but do I need to reformat this in my dns as before with all parameters in one block? And does anyone know the reason behind this?

Eaten by a Grue

Asked: 2013-03-07 03:00:55 +0800 CST

How can I change the name of Remote Desktop in Ubuntu 12.04

2

I am using Gnome Classic DE with Ubuntu 12.04. The Vino VNC server is functioning perfectly but it annoyingly advertises itself on the LAN as "(user)'s remote desktop on (server)".

I've looked at gsettings list-recursively org.gnome.Vino and there doesn't appear to be an easy way to change this in Vino's settings. Seen this asked a few other places around the net with no answers so far.

Any help would be greatly appreciated.

New default user group "users"

rdiff-backup tempdir appears to be empty

Stuck on 20.04.1 LTS

Cannot increase MySQL table_open_cache in Ubuntu 20.04

Where are Ubuntu 18 network shares configured?

undefined parameters in /etc/postfix/master.cf

MySQL update overwrites collation

Permission denied using "man"

Wrongly named variables in mysqld.cnf (Ubuntu 16.04)

Block port on one network address

How can I find all the possible cron settings?

Error updating mailman

keep iptables up to date

iptables-persistent not uninstalling

opendkim-genkey txt record in Ubuntu 14.04

How can I change the name of Remote Desktop in Ubuntu 12.04

How to install Google Chrome

Is there a command to list all users? Also to add, delete, modify users, in the terminal?

How to delete a non-empty directory in Terminal?

How to unzip a zip file from the Terminal?

How can I copy the contents of a folder to another folder in a different directory using terminal?

How do I install a .deb file via the command line?

How do I run .sh scripts?

How do I install a .tar.gz (or .tar.bz2) file?

How to list all installed packages

Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?