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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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Why (or how) does the number of open file descriptors in use by root exceed ulimit -n?

Our server recently ran out of file descriptors, and in regards to that I have some questions. ulimit -n is supposed to give me the maximum number of open file descriptors. That number is 1024. I checked the number of open file descriptors by…
oligofren
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Is DRBD the only viable block replication solution for Linux?

I've found myself needing redundant storage at a block level. File-level replication (Gluster, GFS, etc) does not work for my use case. It looks like DRBD is the go-to solution for block replication. There don't seem to be too many other sane…
Charles
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Linux mdadm software RAID 6 - does it support bit corruption recovery?

Wikipedia says "RAID 2 is the only standard RAID level, other than some implementations of RAID 6, which can automatically recover accurate data from single-bit corruption in data." Does anyone know if the RAID 6 mdadm implementation in Linux is one…
sa289
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remove line break using AWK

I am facing some problem regarding my bash script. Below is my bash code : #!/bin/bash cd /root/Msgs/TESTNEW/new file=myfile.txt var1=$(awk '(NR==30){print $2}' $file) var2=$(awk 'NR>=38 && NR<=39' $file) var3=${var2// /+} curl…
user119720
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Easiest way for fast transfer of files between linux servers?

I need to transfer files from one CentOS server to another. Will transfer 5MB files about every 10 minutes. Do not need encryption. What is an easy was for fast transfer of files? Is there something simpler than ftp? Thanks!
Alex L
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Determine Location of Inode Usage

I recently installed Munin on a development web server to keep track of system usage. I've noticted that the system's inode usage is climbing by about 7-8% per day even though the disk usage has barely increased at all. I'm guessing something is…
Dave Forgac
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Disk space usage doesn't add up with df & du

I'm trying to free up some disk space - if I do a df -h, I have a filesystem called /dev/mapper/vg00-var which says its 4G, 3.8G used, 205M left. That corresponds to my /var directory. If I descend into /var and do du -kscxh *, the total is…
Codecraft
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Copy a range of files in command line (ZSH/BASH)

I have a list of files with consecutive numbers as suffixes. I would like to copy only a range of these files. How can I specify a range as part of my cp command. $ls P1080272.JPG* P1080273.JPG* P1080274.JPG* P1080275.JPG* P1080276.JPG*…
Amjith
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How to configure Samba to allow root user for full control to the particular share?

$(subj), it appears to be what root user is denied by default for all of the shares. I'm trying to reproduce Windows administrative share.
user539484
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To yum update? Or not?

please forgive this rather straightforward question. First off, I'm not a sysadmin, and my experience with Linux is somewhat limited. About 3-4 months ago, I set up a CentOS server in work, for a variety of reasons. We are using it as a…
John McCollum
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How can I tell if a system rebooted as well as the time of the reboot by looking at the system logs?

How can I tell if a Linux system rebooted and determine the time of the reboot by looking at the system logs, such as /var/log/messages?
Jack Z
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btrfs-enabled backup solution

With btrfs hitting production in Oracle EL 14th this month (together with working fsck and scrubbing from Linux 3.2) I was thinking of redesigning my current backup solution to utilise it. Note that I'm thinking about doing it for small amounts of…
Hubert Kario
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how many user accounts can a unix-like OS host?

Let's say I want to have a server with as many user accounts as possible. How many is the max? I want millions of user accounts. Is that crazy? I'd host dozens of load-balance mirrors of the box, and user data would be stored on a highly available…
Chris Hinkle
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max files per directory in ext4

I manage an application that contains a filestore in which all the files are stored with the filenames equal to their md5 sums. All files are stored in one directory. Currently there are thousands, but soon their should be millions of files on the…
Jeroen Ooms
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Strange bash history behaviour when running multiple sessions

How is command line history stored when I use multiple terminal windows? I know it is stored in .bash_history but I can't see the logic on what history is used if I open new window. It almost feels nondeterministic in a sense that I never know what…
Alex Gitelman
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