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Questions tagged [centos]

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Questions specific to the CentOS Linux distribution. Use this tag if your question relates to how the CentOS distribution affects your problem; do not use it if you just happen to be using CentOS and your question is about a specific configuration detail or syntax.

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13
votes
2answers
11k views

Why is there a discrepancy in disk usage reported by df and du? [duplicate]

I have a Linux CentOS server, the OS+packages used around 5GB. Then, I transferred 97GB data from a Windows server to two folders on this Linux server, after calculated the disk usage, I see the total ...
5
votes
2answers
13k views

Using Awesome window manager on CentOS 7

Awesome works fine on Fedora 19, so it should work on CentOS 7, right? Well, I tried and failed to get it to work. After a long time, I managed to compile it from source and set GDM to boot from an ~/...
14
votes
2answers
22k views

Separate Network Traffic on Two Network Interfaces

Could you lend your expertise in understanding how to go about configuring the separation of network traffic on two network interfaces? As I understand thus far, static routes are used for network ...
6
votes
1answer
10k views

Rename All Files with a Certain Name

I'm trying to find certain files with the name "stringx" and replace the name (but not the extension) with "stringy". So basically for stringx.txt and stingx.cs, I'd want stringy.txt and stringy.cs. I'...
16
votes
4answers
20k views

Systemd kills service immediately after start

I'm writing systemd unit files for OSSEC HIDS. The problem is that when systemd starts the services it immediately stops them. When I use the following ExecStart directive everything is working fine. ...
7
votes
1answer
3k views

Why is the rename utility on Debian/Ubuntu different than the one on other distributions, like CentOS?

On CentOS, the rename command uses two simple strings, from and to. rename from to file... while on Debian/Ubuntu it uses a perl-style regular expression. rename [ -v ] [ -n ] [ -f ] perlexpr [ ...
17
votes
5answers
17k views

How do I drop root privileges in shell scripts?

The "--up" option in OpenVPN is normally used for routing etc. And so it is processed before OpenVPN drops root privileges to run as nobody. However, I am invoking shell scripts that need to run as an ...
16
votes
5answers
20k views

Moved bin and other folders! How to get them back?

I accidentally moved all folders from root to a subfolder. (/bin, /etc, /home, /lib, /usr... all moved) The only ones that were not moved, since they were in use, are /bak, /boot, /dev, /proc, /sys. ...
207
votes
3answers
1.0m views

How to install Desktop Environments on CentOS 7?

I have recently installed CentOS 7 (Minimal Install without GUI) and now I want to install a GUI environment in it. How can I install Desktop Environments on previously installed CentOS7 without ...
76
votes
2answers
49k views

What's the difference between /usr/lib/systemd/system and /etc/systemd/system?

Before all the unit files were in /etc/systemd/system/ but now some are showing up in /usr/lib/systemd/system (<- on CentOS, or /lib/systemd/system <- on Debian/Ubuntu), what is the difference ...
3
votes
2answers
8k views

Why booting into rescue mode menu doesn't do anything?

When I enter into grub menu, I get two entries : CentOS Linux (3.10.0-514.21.1.el7.x86_64) 7 (Core) CentOS Linux (0-rescue-e1ac24cbe9f94f2caa228d77e027be8b) 7 (Core) When I boot into the second line ...
107
votes
3answers
106k views

How to shrink root filesystem without booting a livecd

I find myself needing to rearrange a system's partitions to move data previously under the root filesystem into dedicated mount points. The volumes are all in LVM, so this is relatively easy: create ...
47
votes
5answers
51k views

How can I limit the bandwidth used by a process?

I have a CentOS 5.7 server that will be backing up its files nightly. I am concerned that visitors to the various sites that the server hosts will experience degraded performance while the backup is ...
24
votes
2answers
23k views

How to colorize output of ls ?

I'm running CentOS in Linux text mode. When I run the command ls /usr/, the output is too hard to read (dark blue on black). How can I change the text coloring?
16
votes
4answers
26k views

What are the different ways that a message can be displayed to a bash shell after a user logs in?

I have a CentOS 5.7 VPS using bash as its shell that displays a branded greeting immediately after logging in via SSH. I've been trying to modify it, but can't seem to find where it is in the usual ...
-9
votes
1answer
339 views

(URGENT) How to change permissions and access on a Samba Network Share hosted on CentOS7? [closed]

I have a Samba share on my local network hosted on a CentOS7 machine (32bit so can't use any answers involving EPEL-RELASE REPOS) and want to configure the permissions and let specific users have ...
173
votes
11answers
272k views

Is CentOS exactly the same as RHEL?

I'm sure this question has been asked again and again elsewhere (I did not find anything specific to CentOS vs RHEL in SE), but I would still like to ask and confirm a few specific points. I am well ...
103
votes
2answers
144k views

How do I display log messages from previous boots under CentOS 7?

Executing journalctl under a CentOS 7 system just prints messages generated after the last boot. The command # journalctl --boot=-1 prints Failed to look up boot -1: Cannot assign requested ...
57
votes
11answers
145k views

CentOS no network interface after installation in VirtualBox

I have Ubuntu 12.10 on which I installed virtual box on which I setup Centos 6.4 i386. On Ubuntu I have: 3.5.0-17-generic kernel running. On virtual box I install Centos 6.4 and everything works fine,...
18
votes
3answers
53k views

What does eno mean in network interface name 'eno16777736' for CentOS 7 or RHEL 7?

Under consistent network device naming scheme, what does 'eno' stand for in network interface name eno16777736 for CentOS 7 or RHEL 7?
3
votes
2answers
2k views

Why doesn't my blockdev config change execute from rc.local on reboot

I am (probably obviously) a relatively new Linux user, so I'm already bracing for the barrage of "why aren't you doing it this way instead..." comments. I'd love to hear them...but I would also really ...
1
vote
1answer
8k views

How to update Apache and PHP using SCL?

I'm testing an upgrade of PHP using SCLs. The testing is happening on a local VM so its OK to break things as we develop a procedure. Following The SCL Repositories I was able to update Python to 2.7....
173
votes
3answers
608k views

ifconfig command not found

I've just installed CentOS7 as a virtual machine on my mac (osx10.9.3 + virtualbox) .Running ifconfig returns command not found. Also running sudo /sbin/ifconfig returns commmand not found. I am root. ...
137
votes
10answers
556k views

How can I fix “cannot find a valid baseurl for repo” errors on CentOS?

I finished installing CentOS 6, but when I tried running yum update I got: [root@centos6test ~]# yum update Loaded plugins: fastestmirror, refresh-packagekit Determining fastest mirrors Could not ...
53
votes
3answers
201k views

How to update glibc to 2.14 in CentOS 6.5

I want to install Android NDK on my CentOS 6.5 machine. But when I ran the program, it says it needs glibc 2.14 to be able to run. My CentOS 6.5 only has Glibc 2.12 installed. So I tried to update ...
57
votes
4answers
146k views

How to change systemd service timeout value?

In the company I am working now there is a legacy service and its init script is using old SysvInit, but is running over systemd (CentOS 7). Because there's a lot of computation, this service takes ...
50
votes
2answers
73k views

CentOS: List the installed RPMs by date of installation/update?

I'm on a CentOS machine. I updated and installed some packages a few weeks back, but I don't remember the name of every package or the names of every dependency. I used yum. Can I list the packages ...
52
votes
10answers
161k views

Equivalent of update-grub for RHEL/Fedora/CentOS systems?

In Ubuntu (and I guess in Debian too) there is a system script named update-grub which automatically executes grub-mkconfig -o with the correct path for the grub configuration file. Is there any ...
36
votes
6answers
125k views

What is the default idle timeout for OpenSSH?

I can't seem to find an answer to this simple question, which I need for some compliance documentation. On a default install of CentOS 6.5 (OpenSSH 5.3p1-94.el6), after how long of being idle will ...
30
votes
2answers
5k views

What is the difference between shutdown 18:00 and at 18:00 shutdown?

at 18:00 shutdown now and shutdown 18:00 , are they starting the same service? Do they work the same way?
11
votes
3answers
41k views

How to make NetworkManager add a DNS server at the top of /etc/resolv.conf?

Right now, my /etc/resolv.conf looks like this: # Generated by NetworkManager nameserver 10.165.246.33 nameserver 192.135.82.60 nameserver 10.165.74.2 The first two nameservers are automatically ...
4
votes
1answer
1k views

Making “at” work on macOS

I am working on a CentOS server and schedule a task with command at # echo "touch a_long_file_name_file.txt" | at now + 1 minute job 2 at Wed Oct 31 13:52:00 2018 One minute later, # ls | grep ...
4
votes
2answers
2k views

Commands for determining level of usage of server

I am scripting a new program that will connect to a cluster of machines in a VM park, and hopefully check their level of usage. The VM clients are a combination of RHEL and CentOS, and runs on ...
10
votes
2answers
6k views

Is it possible to create a directory and file inside /proc/sys?

I am running CentOS 6.2 and I need to create a subdirectory named "crypto" inside /proc/sys. Inside /proc/sys/crypto, I need to create a file named test which contains the value "1".
8
votes
1answer
5k views

Hard link permissions behavior different between CentOS 6 and CentOS 7

I'm getting a permissions error in CentOS 7 when I try to create a hard link. With the same permissions set in CentOS 6 I do not get the error. The issue centers on group permissions. I'm not sure ...
0
votes
2answers
497 views

Permanent network drive mount in fstab not working (due to network not being online whilst attempting to mount)

I have a network drive hosted on a Windows10 Machine, it mounts fine to my CentOS7 machine through the command: sudo mount -t cifs //ipaddress/sharedfoldername /mountpoint --verbose -o credentials:/...
162
votes
2answers
308k views

In CentOS, what is the difference between yum update and yum upgrade?

What is the difference between yum update and yum upgrade, and when should I use one over the other?
52
votes
4answers
216k views

Why the default eth0 interface is down by default on CentOS?

I am already a little bit familiar with Linux distros like Debian or Ubuntu (yeah, very similar) but I wanted to try Red Hat based - CentOS 6.2. I have installed it on my Windows 7 host in VirtualBox ...
23
votes
4answers
83k views

Windows boot option is missing after installing CentOS 7, how can I get it back?

I recently installed CentOS 7 on a machine that has been running Windows 7. I did a dual boot installation and installed CentOS in a partition. But when I boot up my machine, it only gives me two ...
18
votes
5answers
51k views

How do I safely delete old kernel versions in CentOS 7?

I might be encountering odd symptoms resulting from competing kernels in CentOS 7. So how do I safely delete the old kernels? And how do I know which kernel is the newest one? Below is the ...
11
votes
2answers
102k views

What is the best way to add a permanent route?

I need to add a route that won't be deleted after reboot. I read these two ways of doing it : Add ip route add -net 172.X.X.0/24 gw 172.X.X.X dev ethX to the file /etc/network/interfaces or ...
5
votes
1answer
22k views

CentOS conservative governor, nice error

I changed my CentOS 6 CPU governor from ondemand (the default one) to conservative and got this after restarting the cpufreq service: /etc/rc5.d/S13cpuspeed: line 88: /sys/devices/system/cpu/...
11
votes
2answers
37k views

Change default path for when I SSH in to CentOS server?

I have a CentOS 5.7 web server, and I want to change the default place I land in when connecting using SSH. Currently I land in /home/username, and I want to land in /home instead. I've gone in as ...
3
votes
2answers
9k views

Change all folder permissions with 1 command

Within my web application directory, how can I change all my folder permissions to rwxr-xr-x (755)? And how can I change all file permissions to rw-r--r-- (644)? I want to change all folders and files ...
2
votes
2answers
2k views

How can I make a process I start during an SSH session run after the session has ended? [duplicate]

Possible Duplicate: Keep SSH Sessions running after disconnection. I have a process which is basically a web-server, I start it during an SSH session. However, when I leave the session (by ...
48
votes
2answers
90k views

CentOS 6 “Default” Installation Options

Can someone tell me the difference between a Desktop Install, a Basic Server install, and a Minimal Install? During installation, it doesn't give a description and I can't find documentation on it ...
52
votes
4answers
80k views

yum Error:rpmdb open failed

I'm trying to run yum update and I'm running this error: rpmdb: PANIC: fatal region error detected; run recovery error: db3 error(-30974) from dbenv->open: DB_RUNRECOVERY: Fatal error, run ...
20
votes
1answer
159k views

Install Apache 2.4 on CentOS using yum

I need Apache 2.4 in CentOS because with Apache 2.2 mod_proxy_wstunnel is not possible. I have tried this, but unfortunately its for RHEL. After installing, I can't execute the Apache 2.4. Can anyone ...
34
votes
12answers
143k views

“Symbolic link not allowed or link target not accessible” / Apache on CentOS 6

I've got a brand new CentOS 6 installation, which has a symlink in the document root to my development files: [root@localhost html]# ls -l total 4 -rwxrwxrwx. 1 root root 0 Sep 18 20:16 index.html -...
8
votes
1answer
93k views

How can I create an SFTP user in CentOS?

I'd like to give temporary SFTP access to a support guy. How do I create an SFTP user? And how can I delete it once the job is done? Also, how do I specify a home directory for them? Can I prevent ...

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