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Questions tagged [linux]

Linux is the generic term for a UNIX-like open source operating system based on the Linux kernel.

GNU/Linux is a UNIX-like Open Source operating system. Linus Torvalds originally wrote the Linux kernel with contributions from others on the MINIX usenet board. Since then, Linux had thousands of developers, both paid by companies and volunteers. The main system tools and libraries for GNU/Linux are sourced from the GNU Project, hence the nomenclature GNU/Linux (GNU Toolchain over Linux Kernel). The Linux kernel is licensed under the GPL v2 license.

There are many different Linux Distributions (sometimes shortened to distro), which consist of software applications packaged and provided with the Linux kernel, being Slackware the oldest active distro and Debian, Red Hat and CentOS among the most used on Internet servers¹.

The Linux kernel is commonly run on servers but is highly portable and is used in a variety of applications, from wireless routers and cell phones to clusters and super computers with thousands of nodes and processors.

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What is the difference between syslog, rsyslog and syslog-ng?

I am a bit confused in syslog, rsyslog and syslog-ng. From where can I get the source code for syslog()? Is there any difference between rsyslog and rsyslogd?
StackUser
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Drawbacks of mounting a filesystem with noatime?

Having every file be updated just when accessing them sounds like a waste. What's the catch with mounting a file system with the noatime option. What kind of applications/servers relies on the access time?
nos
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Apache 2 startup warning: NameVirtualHost *:80 has no VirtualHosts

When my Ubuntu Apache server (Apache 2) starts up I get a warning message that reads: [warn] NameVirtualHost *:80 has no VirtualHosts However, the web server is working fine. What might I have wrong in my site's configuration to make it give me…
Kit Roed
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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 e6eacc985fea729b2d5bc74078632738: Input/output error ls: cannot access…
jaymoo
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How do I determine the block size of an ext3 partition on Linux?

How do I determine the block size of an ext3 partition on Linux?
mike
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Linux FHS: /srv vs /var ... where do I put stuff?

My web development experience has started with Fedora and RHEL but I'm transitioning to Ubuntu. In Fedora/RHEL, the default seems to be using the /var folder while Ubuntu uses /srv. Is there any reason to use one over the other and where does the…
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What steps do you take to secure a Debian server?

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 programs you use for it. I want part of this question…
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Does memtest86+ test memory which is used to run itself?

One of the common server failure scenarios is bad DRAM, sometimes even when ECC memory is used. memtest86+ is one of the most useful tools to diagnose DRAM problems. As it loads itself at the start of the memory, I've been wondering if memtest86+…
Robin
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How to ping in linux until host is known?

How can I ping a certain address and when found, stop pinging. I want to use it in a bash script, so when the host is starting up, the script keeps on pinging and from the moment the host is available, the script continues...
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Why are my XFS filesystems suddenly consuming more space and full of sparse files?

I've run XFS filesystems as data/growth partitions for nearly 10 years across various Linux servers. I've noticed a strange phenomenon with recent CentOS/RHEL servers running version 6.2+. Stable filesystem usage became highly variable following…
ewwhite
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best way to debug nginx rewrite rules in config file?

I have a bunch of rewrite rules that I have to port from apache to nginx. It's a rather painful process because I'm not able to see if my rewrite rules and "if" conditions are working as I want them to. Apache did have debugging for its rewrite…
Jiho Kang
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Cannot SSH: debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY

We have a server on Amazon EC2 running SSH is on a standard (22) port. I placed my public key at the /.ssh/authorized_keys file. The fun thing is that yesterday it was working great! But today, I don't know what happened! I just can't log…
bakytn
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Linux: productive sysadmins without root (securing intellectual property)?

Is there any way to make a seasoned Linux syadmin productive without giving him full root access? This question comes from a perspective of protecting intellectual property (IP), which in my case, is entirely code and/or configuration files (i.e.…
Matt
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Executing a command as a nologin user

I've recently set up my server so that my suPHP 'virtual' users can't be logged into by using this article My issue now is that before when I ran a rake command for my Ruby on Rails application running on the server, I used su to go into www-data…
user82250
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Hidden Features of Linux

Following in the spirit of Hidden Features of PowerShell and various others on Stack Overflow, what Linux commands or combinations of commands do you find essential in your work? Also See: Hidden Features of MySQL Hidden Features of PowerShell…
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