Red Hat Enterprise Linux (RHEL) is a commercially supported Linux distribution.

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23
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What is the difference between these commands for bringing down a Linux server?

Reading "What is the difference between Halt and Shutdown commands?" , I generally have an idea what does the command shutdown does, with or without -h/-r options. The "halt" command performs ...
2
votes
2answers
580 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 ...
9
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4answers
65k views

How can we change root password?

If we don't know the root password and don't have root access to the machine, how can we change the root password?
15
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3answers
11k views

.bash_profile not sourced when running su

I have a user, say user1, which has modifications to its .bash_profile, one of them changing the PATH, e.g.: export PATH=/some/place:$PATH. This change works fine if I log on as user1 or do a su - ...
17
votes
3answers
11k views

Piping from grep to awk not working

I am trying to grep the ongoing tail of file log and get the nth word from a line. Example file: $ cat > test.txt <<EOL Beam goes blah John goes hey Beam goes what? John goes forget it Beam ...
2
votes
1answer
3k views

.bashrc doesn't get executed

I have a user (non-root) which has a ~/.bashrc file with some aliases in it. But it doesn't look like the file is executed at log in time. If I do source ~/.bashrc then it does what it's supposed to. ...
5
votes
3answers
8k views

RHEL: Creating stable names for network interfaces

We have a RHEL 5.5 box with 8 interfaces. And the eth interface naming is flip flopping. Sometimes eth0 comes up on physical port 7th, and sometimes on another physical port. We want the naming to ...
8
votes
2answers
6k views

Installing a package locally to a user - best practices?

I want to install Git locally to a user on a RHEL server (I don't have root access) What would be your cleanest/ most organized way of installing software to a local user account? Installing ...
6
votes
4answers
21k views

Pseudo-terminal will not be allocated because stdin is not a terminal

I'm trying to set up automatic SSH hopping through a server which doesn't have nc. This works from the command line: ssh -A gateway ssh steve@target (I have added my public key to the SSH agent). ...
6
votes
3answers
24k views

How to clear memory cache in Linux

Is there any command that by using I can clean the cache in RHEL? I used this command: sync; echo 3 > /proc/sys/vm/drop_caches but it didn't work.
14
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3answers
15k views

Does RHEL execute all cronjob files under /etc/cron.d/*?

This is a RedHat Enterprise Linux 5 system (RHEL). We manage this system using Cfengine. We have several cronjobs which are running twice as often as usual. I checked the cronjobs under /etc/cron.d/ ...
13
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2answers
12k views

/dev/tcp listen instead of nc listen

With a netcat listener like: nc -l <port> < ~/.bashrc I can grab my .bashrc on a new machine (doesn't have nc or LDAP) with: cat < /dev/tcp/<ip>/<port> > ~/.bashrc My ...
3
votes
1answer
638 views

Writing triggers for mcelog

Just starting to look into mcelog for the first time (I've enabled it and seen syslog output before, but this is the first time I'm trying to do something non-default). I'm looking for information on ...
15
votes
7answers
6k views

Is there a difference of stability between Linux distros?

I've using Debian since 2010 for some home purposes and it has been stable. Is Debian still a good option if I need a server for heavy network, cpu, disk and memory usage? Last month I listened to ...
14
votes
3answers
12k views

how to run new software without updating GLIBC?

I installed Mathematica 9 on an old Red Hat Enterprise Linux AS release 4 system. After the installation, I tried to start Mathematica, but following message came out: ...
7
votes
2answers
9k 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 ...
5
votes
2answers
2k views

Is there a way to install and remove packages in a single yum command?

Is there a way to add and remove packages at the same time with a single yum command? For example, installing postfix and removing sendmail without running two separate commands/transactions.
1
vote
1answer
17k views

Uninstall JDK rpm to reinstall

Where do I find the JDK install to uninstall? @terdon had explained using an rpm type download so it would be easier to uninstall, but I cannot find it.
7
votes
1answer
20k views

How do I install g++ on RHEL6?

This question seems to have been asked here already. My IT department installed the OS so I don't know how to register it properly but I do have root access. Is there a way to get the same packages ...
5
votes
2answers
32k views

Setup static IP in redhat 6

I installed Redhat 6 x86_64. I am using the Network connection screen to set a static IP address like below (I want two PC's in my house to see each other: one Redhat PC and one Mac) 192.168.0.5 ...
1
vote
1answer
8k views

doing OpenLDAP config changes in RHEL 6

I've been configuring OpenLDAP on RHEL 6 and its seems you have run the following to rebuild the config dirs. I'm ok with that, but my issues is, say I want to change the server passwd, do I have to ...
7
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2answers
5k views

How can I install ncdu on Red Hat?

The answers provided to this question doesn't help. I'ved tried yum install ncdu But I'm getting No package ncdu available
7
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4answers
9k views

How to install software on Red Hat?

What's the simplest way to download/install software on Red Hat Linux (from bash command line)?
5
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1answer
953 views

rc.local with read will not echo key strokes

I'm using CentOS 6.4 and have a small problem with using read in /etc/rc.local file. It will allow keyboard entry but does not echo any of the key strokes during input. This is something that worked ...
4
votes
2answers
154 views

Separate Network Traffic on Two Network Interfaces

I am not an R&S professional, so much of that realm of computing escapes me. Could you lend your expertise in helping understand how to go about configuring the separation of network traffic on ...
3
votes
1answer
689 views

Can't get past EFI to install RHEL on HP Itanium Server

When I am trying to install RHEL (6.3, 5.8, 4.8) on an HP Integrity Server rx2660 Itanium with 4GB RAM, I keep getting to the same point which is Loading file efi\boot\initrd.img...done After that ...
1
vote
3answers
2k views

Using nohup to keep a script running indefinitely

I am very new to Linux and I've only been using it to SSH to my web server using Putty. The issue I am having is this: Basically I've got 2 php scripts. One get_tweets.php constantly listens for ...
1
vote
2answers
5k views

How to extend LVM in RHEL 5.6

I need to extend the LVM on one server. This is the output of df -h: Filesystem Size Used Avail Use% Mounted on /dev/cciss/c0d0p2 58G 26G 29G 48% / ...
1
vote
1answer
941 views

NIS and autofs error

I am trying to share the home directory of a NIS user using NFS and autofs. During testing, I get the following error message: Could not chdir to home directory /home/guest/nis1: Permission denied ...
0
votes
1answer
190 views

Systemd kills service immediately after start

I'm writing systemd unit file for OSSEC HIDS. Problem is that when systemd starts service it immediately stops them. When I use that ExecStart directive all working fine. ...
-1
votes
1answer
275 views

routing based on source IP [closed]

Is it possible to configure routing based on source ip? For example, if I have source IP 10.0.0.0, then all the traffic will go via the specific interface or would be sent to specific default gateway. ...
59
votes
7answers
20k views

What is the Linux equivalent to C:\Program Files?

I understand that in Windows as well as Linux and Unix, a program|application|software can be installed in any directory. Also if packages are installed using the distribution's packaging system, ...
52
votes
10answers
76k 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 ...
12
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2answers
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( /etc/sysconfig/iptables ) “Manual customization of this file is not recommended.” Why?

Editing this file directly /etc/sysconfig/iptables can save me so much headaches so much time and so on... and yet on the very top of the file it says.. Manual customization of this file is not ...
12
votes
7answers
47k views

How to boot Linux to command-line mode instead of GUI?

I am using 32-bit Red Hat Linux in my VM. I want to boot it to command-line mode, not to GUI mode. I know that from there I can switch to GUI mode using startx command. How do I switch back to ...
20
votes
3answers
16k views

Why SSH takes a long time to Connect

I have noticed that some Linux Servers in Network takes long time to connect using ssh. Situations: There are two situations I have faced: On some servers some times it takes a long time to ask ...
13
votes
1answer
2k views

Why does Red Hat Linux use such an old kernel?

Why does RHEL (and its derivatives) use such an old kernel? It uses 2.6.32-xxx, which seems old to me. How do they support newer hardware with that kernel? As far as I know these kind of distributions ...
8
votes
3answers
16k views

How to set global environment variables at boot through a script, and have them available for an application that runs before login?

I have a service that runs at boot, and in that service it calls a bash script in the background that exports some environment variables. The problem I'm having is that those environment variables ...
4
votes
3answers
15k views

what is pts/0 and (:0.0) in linux by type who am i

When I type the command: [root@degeneration Desktop]# who am i root pts/0 2013-04-12 15:08 (:0.0) What is pts/0 and what is meant by (:0.0)?
6
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2answers
14k views

How to add an item to the Applications menu?

How can I add an application to Applications > Internet in Gnome Desktop running on CentOS 6.4? Per this old Docs link, it suggests to edit /etc/xdg/menus/applications.menu. How can I add ...
2
votes
1answer
1k views

cat file to multicast

I have a text file (test.txt) which represents captured network data. The actual protocol is text-based, with NULL line endings, so this isn't a problem. I need to run this test captured data ...
2
votes
2answers
494 views

Where to apply xmodmap for systemwide usage?

I need to apply a custom xmodmap for all users at the start. Where do I need to put it? I have thought at /etc/rc.local? Does this make sense?
14
votes
1answer
16k views

Unable to delete file, even when running as root

I am in the process of migrating a machine from RHEL 4 to 5. Rather than actually do an upgrade we have created a new VM (both machines are in a cloud) and I am in the process of copying across data ...
7
votes
2answers
7k views

Which of these three commands is telling the TRUE Redhat release information

I was checking for the Redhat release so this time I used three different commands. Two commands gave the same result but the third command gave different result. Which one is right. ...
7
votes
3answers
2k views

Once sudo su'd to root, is there a command to see my username?

I have sudo rights on a redhat box; once I've sudo su - to become root in a shell, are there any commands I can run to see what username I su'd FROM?
6
votes
2answers
1k 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". I have tried ...
5
votes
1answer
4k views

How do I reduce the size of locale-archive?

I have a need to reduce the size of the locale-archive file on some of my RHEL6 systems. Here is that file on my system: [root@-dev-007 locale]# ls -l total 96800 -rw-r--r--. 1 root root 99158704 ...
5
votes
3answers
2k views

Performing accurate snapshot and incremental backups to a remote server

I have a few Ubuntu (and potentially RHEL) servers I'd like to back up to a central backup server (via rsh/SSH). I'd like to do both snapshot and incremental backups. The goal is that if one of the ...
5
votes
3answers
4k views

Change /dev/sd* for USB Linux install?

I am trying to install Scientific Linux 6.1 (which is literally RedHat Enterprise Linux without the branding) by booting its installer from my USB drive. The installer starts fine, but two things ...
4
votes
1answer
2k views

Maximum memory usable by a 32 bit RHEL 6 system

I have installed a 32 bit RHEL OS on a 64 bit system. From the wiki page of PAE: The Linux kernel includes full PAE mode support starting with version 2.3.23, with Linus Torvalds mentioning ...