Questions tagged [debian]

Debian is a popular and influential GNU/Linux distribution. Questions here should generally be about Debian Server.

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362 votes
5 answers

Anyone else experiencing high rates of Linux server crashes during a leap second day?

*NOTE: if your server still has issues due to confused kernels, and you can't reboot - the simplest solution proposed with gnu date installed on your system is: date -s now. This will reset the ...
Bron Gondwana's user avatar
262 votes
11 answers

How can I run Debian stable but install some packages from testing?

Say you're running a server and you don't want to upgrade to Testing (Squeeze) from Stable (Lenny) to just install a required package or two. What's the best way of installing only certain packages ...
Gareth's user avatar
  • 8,573
234 votes
4 answers

What's the best way of handling permissions for Apache 2's user www-data in /var/www?

Has anyone got a nice solution for handling files in /var/www? We're running Name Based Virtual Hosts and the Apache 2 user is www-data. We've got two regular users & root. So when messing with ...
Gareth's user avatar
  • 8,573
156 votes
6 answers

List of files installed from apt package

How do I get a list of files that were or will-be installed when I apt-get a package? Conversely, can I find what package(s) caused a particular file to be installed?
David Nehme's user avatar
  • 2,066
143 votes
3 answers

How to remove the "installed manually" flag and revert to "automatically installed" with apt-get?

To compile something, I needed the zlib1g-dev package to be installed so I launched an apt-get install zlib1g-dev. apt-get informed me nicely that the package was already auto-installed because of ...
Steve Schnepp's user avatar
138 votes
13 answers

How do I get apt-get to ignore some dependencies?

How do I make apt-get ignore some dependencies? For example, I wanted to install mailx so I can use it to send email from cron scripts/report-generating tools. However, installing mailx also installs ...
FrancisV's user avatar
  • 1,776
111 votes
8 answers

How to install/change locale on Debian?

I've written a web application for which the user interface is in Dutch. I use the system's date and time routines to format date strings in the application. However, the date strings that the system ...
Hongli Lai's user avatar
  • 2,242
105 votes
8 answers

How to determine JAVA_HOME on Debian/Ubuntu?

On Ubuntu it is possible to have multiple JVMs at the same time. The default one is selected with update-alternatives. But this does not set the JAVA_HOME environment variable, due to a debian policy. ...
Witek's user avatar
  • 1,422
105 votes
6 answers

list all packages from a repository in ubuntu / debian

is there a command to see what packages are available from a certain ppa repository?
opensas's user avatar
  • 1,181
100 votes
9 answers

mysqldump to a tar.gz

Usually after dumping a MySQL database with mysqldump command I immediately tar/gzip the resultant file. I'm looking for a way to do this in one command: So from this: mysqldump dbname -u root -p &...
pygorex1's user avatar
  • 1,181
99 votes
11 answers

How can I export the privileges from MySQL and then import to a new server?

I know how to export/import the databases using mysqldump & that's fine but how do I get the privileges into the new server. For extra points, there are a couple of existing databases on the new ...
Gareth's user avatar
  • 8,573
95 votes
3 answers

Is it possible to reboot a Linux OS without rebooting the hardware?

Is there a way to reboot a Linux system (Debian in particular) without rebooting the hardware? I have a RAID controller that takes a bit to get itself running before the OS starts up, and I would ...
lacrosse1991's user avatar
  • 1,447
85 votes
8 answers

How can I list my open ports on Debian?

What is the command to display a list of open ports on a Debian server? I tried netstat -a | egrep 'Proto|LISTEN' but I would like something more specific that actually lists the port number.
leonel's user avatar
  • 989
83 votes
1 answer

What does "debconf: delaying package configuration, since apt-utils is not installed" mean?

I have just installed Debian and I was just installing some packages using apt-get instal when I saw this message: debconf: delaying package configuration, since apt-utils is not installed What does ...
David's user avatar
  • 1,077
81 votes
5 answers

Best location to keep SSL certificates and private keys on Ubuntu servers?

On Ubuntu, it looks like the best place for a private key used to sign a certificate (for use by nginx) is in /etc/ssl/private/ This answer adds that the certificate should go in /etc/ssl/certs/ but ...
Adam Nelson's user avatar
  • 1,677
80 votes
8 answers

What should I do when I got the KEYEXPIRED error message after an apt-get update?

While updating my packages on a debian based system by a sudo apt-get update I've got that error message : Reading package lists... Done W: GPG error: stable/non-US Release:...
paulgreg's user avatar
  • 4,164
78 votes
7 answers

How to check for modified config files on a Debian system?

How to find all Debian managed configuration files which have been changed from the default?
malclocke's user avatar
  • 1,711
78 votes
9 answers

What is the debian-sys-maint MySQL user (and more)?

I have been bitten several times by the 'debian-sys-maint' user that is installed by default on the mysql-server packages installed from the Ubuntu repositories. Generally what happens is I pull a ...
Joe Holloway's user avatar
  • 1,909
74 votes
2 answers

How should an IT department choose a standard Linux distribution?

There is a lot of community feeling about what Linux distributions are appropriate for production server environments and which aren't, however, a lot of this feeling seems religiously based, and ...
wfaulk's user avatar
  • 6,938
69 votes
7 answers

automate dpkg-reconfigure tzdata

I'm using puppet to admin a cluster of debian servers. I need to change the timezone of each machine on the cluster. The proper debian way to do this is to use dpkg-reconfigure tzdata. But I can ...
user avatar
68 votes
8 answers

How to change a SSH host key?

I cloned a server and so they've the same RSA key fingerprint. It seems to be defined in /etc/ssh/ What is the correct way to change that? Thanks.
Pascal Polleunus's user avatar
68 votes
11 answers

Disable a service from starting at all runlevels?

I have a service foo which currently starts at runlevel 3 and above. How can I stop it from doing so, without using update-rc.d foo stop 3 ., which (if I understand it correctly) would turn off the ...
lfaraone's user avatar
  • 1,611
68 votes
3 answers

How do I enable non-free packages on Debian?

How can I enable non-free packages on Debian? I want to install Sun's Java JDK but it's not available to me.
Quiffner's user avatar
  • 683
68 votes
10 answers

Question marks showing in ls of directory. IO errors too

Has anyone seen this before? I've got a raid 5 mounted on my server and for whatever reason it started showing this: jason@box2:/mnt/raid1/cra$ ls -alh ls: cannot access ...
user avatar
66 votes
12 answers

MySQL keeps crashing: InnoDB: Unable to lock ./ibdata1, error: 11

I have a simple webserver (Debian 6.0 x86, DirectAdmin with 1 GB of memory and still 10 GB free space, mySQl version 5.5.9), however the mySQL server keeps crashing and I need to kill all mySQL ...
Devator's user avatar
  • 1,483
66 votes
8 answers

What steps do you take to secure a Debian server? [closed]

I am installing a Debian server which is connected directly to the Internet. Obviously I want to make it as secure as possible. I would like you guys/gals to add your ideas to secure it and what ...
64 votes
3 answers

Docker: failed to add the pair interfaces (operation not supported)

After installing Docker, I am getting an error when I try to run the Hello World example: Error response from daemon: Cannot start container ...
piero-la-lune's user avatar
63 votes
4 answers

Purpose of Debian "sites-available" and "sites-enabled" directories?

Can anyone tell me—in a nutshell—what the purpose of these two directories are in Debian? /etc/apache2/sites-enabled /etc/apache2/sites-available I notice that diffing sites-available/000-default ...
aaaidan's user avatar
  • 732
63 votes
11 answers

How Often Should I Update our Linux Server?

I am responsible for managing both our production server (mail, web, database are all on one server) and our test server. Both are built on Debian. However as I am very new to system administration, I ...
Noah Goodrich's user avatar
62 votes
2 answers

debian packages version convention

I'm using debian/Ubuntu, and get confused about versions of packages. When using dpkg -l command, I get: ii vim 2:7.3.429-2ubuntu2.1 Vi IMproved - ...
cizixs's user avatar
  • 923
62 votes
5 answers

What's the difference between 'useradd' and 'adduser'?

What's the difference between useradd and adduser? When/why should I prefer using one or the other?
lindelof's user avatar
  • 929
59 votes
13 answers

The following signatures couldn't be verified because the public key is not available: NO_PUBKEY

My environment: # uname -a Linux app11 4.9.0-5-amd64 #1 SMP Debian 4.9.65-3+deb9u2 (2018-01-04) x86_64 GNU/Linux # # cat /etc/*release PRETTY_NAME="Debian GNU/Linux 9 (stretch)" NAME="Debian GNU/...
alexus's user avatar
  • 13.2k
59 votes
8 answers

Run a shell script as a different user

What's a good way of running a shell script as a different user. I'm using Debian etch, and I know which user I want to impersonate. If I was doing it manually, I would do: su postgres ./backup_db....
Wadih M.'s user avatar
  • 1,032
57 votes
6 answers

Given a debian source package - How do I install the build-deps?

I have a debian (well technically ubuntu) source package, i.e. the .dsc, the .tar.gz, etc., I want to build this. The dpkg-buildpackage fails, since I don't have all the build dependencies. Normally ...
Amandasaurus's user avatar
  • 31.9k
56 votes
9 answers

What's the difference between apt-get and aptitude?

I don't get why there are two different programs in a minimal install to install software. Don't they do the same thing? Is there a big difference? I have read everywhere to use aptitude over apt-get ...
Thomaschaaf's user avatar
  • 3,092
56 votes
6 answers

How do I force Linux to reacquire a new IP address from the DHCP server?

The environment is Debian, although the answer will apply to all distributions.
55 votes
5 answers

HAProxy graceful reload with zero packet loss

I'm running an HAProxy load balancing server to balance load to multiple Apache servers. I need to reload HAProxy at any given time in order to change the load balancing algorithm. This all works ...
Conor Taylor's user avatar
53 votes
12 answers

How much SWAP space on a 2-4GB system?

How should I decide what size to make my swap on a new Linux machine (Debian) with 2-4 GB of RAM? Do I really need swap space?
C. Ross's user avatar
  • 3,095
48 votes
5 answers

100% non-interactive Debian dist-upgrade

Is there a way to do an apt-get dist-upgrade in Debian that not only automatically answers "yes" to all questions asked, but also uses reasonable defaults as answers to questions that are ...
Alex Balashov's user avatar
46 votes
6 answers

How do you set a locale non-interactively on Debian/Ubuntu?

Usually, I run aptitude -y install locales then dpkg-reconfigure locales to set up locale. Now I want to put it into a shell script, how can I reliably do the following, automatically / non-...
kenn's user avatar
  • 675
45 votes
2 answers

Slow ssh login - Activation of org.freedesktop.login1 timed out

On one of my servers I've noticed really delay on SSH logins. Connecting using the ssh -vvv options the delay occurs at debug1: Entering interactive session. extract of connection: debug1: ...
Alasdair's user avatar
  • 571
44 votes
2 answers

Do some debian builds not have lsb_release?

A .deb package I am releasing expects that it can call lsb_release. One customer using Debian 6.0.5 indicated that the lsb_release command (even in the terminal) produces a command not found error. ...
UsAaR33's user avatar
  • 1,116
43 votes
4 answers

apt-get update/upgrade list without changing anything

I would like to view what packages are available for update/upgrade without actually changing any files becuase there are some packages I wouldn't like to update. Would it then be possible to apt-get ...
John Magnolia's user avatar
43 votes
6 answers

How can I prevent cron from filling up my syslog?

I have a script which needs to be executed each minute. The problem is that cron is logging to /var/log/syslog each time it executes. I end up seeing something like this repeated over and over in /...
user7321's user avatar
  • 1,016
43 votes
1 answer

What exactly will --delete-excluded do for rsync?

I use rsync with great pleasure for backing up my servers, although I do have a question about the --delete-excluded parameter. /usr/bin/rsync -a --delete --numeric-ids --relative --delete-excluded ...
ujjain's user avatar
  • 4,013
42 votes
5 answers

Can dpkg verify files from an installed package?

With rpm -qV openssh-server I will get a list of files that have changed compared to default. ~$ rpm -qV openssh-server S.?....T. c /etc/ssh/sshd_config ~$ Can dpkg on Ubuntu do the same?
Sandra's user avatar
  • 10.4k
38 votes
7 answers

Huge amount of TIME_WAIT connections says netstat

Okay, this is creeping me out - I see about 1500-2500 of these: root@wherever:# netstat Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 localhost:...
KTamas's user avatar
  • 589
38 votes
6 answers

How to use both AllowGroups and AllowUsers in sshd_config?

I'm trying to modify /etc/ssh/sshd_config on my dedicated debian7 server with both AllowUsers and AllowGroups. However I can't seem get both to work together. The Setup There's a user called ...
Johannes's user avatar
  • 483
38 votes
2 answers

Can someone clarify Ubuntu (Debian) dist-upgrade for me?

I've got an Ubuntu 8.04 LTS server. There are several packages which are "kept back" ("the following updates have been kept back") when I do an apt-get upgrade. It's my understanding that I can do ...
Boden's user avatar
  • 5,008
38 votes
7 answers

Unable to ssh to GCE: "Permission denied (publickey)"

I created a VM via Bitnami in Google Compute Engine. Previously, I was able to ssh via the Bitnami web interface. I tried to ssh via terminal on my Mac but kept getting the Permission denied (...
NEO's user avatar
  • 781

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