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

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51
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7answers
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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, ...
32
votes
6answers
48k 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 ...
17
votes
4answers
2k views

What makes CentOS “enterprisey” compared to “generic” distributions like Ubuntu?

What makes CentOS "enterprisey" compared to "generic" distributions like Ubuntu? When I say "enterprisey" I actually mean "better for server deployments". Just a general question, because I was ...
17
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3answers
13k views

Open a RPM on a Mac?

I am on a MacBook Pro running Apple Leopard (Mac OS X 10.5.8). I would like to unpackage a RPM and view the files contained within the wget-1.11.4-2.el5_4.1.src.rpm . I don't need to install the ...
16
votes
3answers
4k 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 ...
14
votes
7answers
4k 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
2answers
7k 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. 1: On some servers some times it takes a long time to ask ...
14
votes
3answers
6k 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: ...
12
votes
3answers
10k 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/ ...
12
votes
3answers
17k views

How can I increase open files limit for all processes?

I can use ulimit but I think that only affects my shell session. I want the limit increased for all processes. This is on Red Hat.
11
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 ...
10
votes
4answers
14k views

can we know the password for the other users if we have root access?

If a person has root access to a particular RHEL machine, will they be able to retrieve the password of the other users?
10
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4answers
1k views

What are the dangers of creating a normal user with UID < 500?

What are the dangers of creating a normal user with UID < 500? Assuming the UID's are not duplicates of existing UID's, what could go wrong? This is not something that I want to do, but something ...
10
votes
4answers
6k views

How can I avoid “Run fsck manually” messages while allowing experimenting with system time changes?

I'm working with a system where we want to allow users to play around with the date and time if they want, and where reboots may happen arbitrarily. This is fine, except for one thing: if there's a ...
9
votes
4answers
10k 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 ...
9
votes
2answers
480 views

( /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 ...
9
votes
3answers
5k 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 - ...
9
votes
1answer
6k 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 ...
9
votes
2answers
669 views

How to prevent fork bomb?

To prevent fork bomb I followed this http://www.linuxhowtos.org/Tips%20and%20Tricks/ulimit.htm ulimit -a reflects the new settings but when I run (as root in bash) :(){ :|:&};: the VM still goes ...
8
votes
2answers
394 views

Temporarily change time

I need to test aspects of my software that only happen at certain times of the day. Rather than waiting whole days (and getting here at 2:00 AM), I'd like to change the time. But I'd rather not ...
8
votes
1answer
427 views

Bandwidth control in linux

How do I control both the inbound and outbound bandwidth in a RHEL 5 router?
8
votes
2answers
388 views

Launching a GUI application in RHEL 5 hangs

When I try to launch any GUI application through a terminal in my RHEL 5.4, it takes a very long time for the GUI to come up. Also, sometimes it just hangs. I see the following messages in the ...
7
votes
4answers
622 views

What distro is the most similar to RHEL 5?

I'm trying to get used to work with linux for a new job, where I will be using RHEL 5, but right now don't have $179 to buy the workstation version from Red Hat store. What free distro would be the ...
7
votes
2answers
5k 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 ...
7
votes
1answer
517 views

What happens when Redhat says: “no more RHEL clones!”

I mean that ex.: CentOS, and Scientific-Linux are the "exact copies" of Redhat Linux. If Redhat would say one day: "I don't allow Redhat clones from now on, I will modify the licence", then what would ...
7
votes
1answer
11k 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 ...
7
votes
1answer
692 views

How to stop users from Switching to Root user

I have disabled the root user login from Sshd.conf file so now no one can login using root user even if they know the password SOMEHOW. Now I have 3 users in server ROOT,EMERG and ORACLE. I want to ...
7
votes
2answers
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?
7
votes
4answers
4k 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)?
7
votes
3answers
5k views

Getting the password expire time

Let me preface this with: I do NOT have root access available. I recently got locked out of my account because I did not know the password expiration was getting close, then elapsed. I want to add a ...
7
votes
2answers
140 views

Are RPMs valid across platforms?

I'm a little confused about RPM's in Red Hat and/or Fedora (and/or other distros?). I can certainly accept that 64-bit RPM's are needed for 64-bit OS'es and 32-bit for 32-bit OS'es but... If I have ...
7
votes
4answers
297 views

How to list all the files used during Linux boot

I would like to get the list of files that are used during the process of Linux boot. We are developing the protected enterprise system based on the RHEL 6.4. The integrity of specified files will be ...
7
votes
3answers
3k views

Why is the theoretical RAM limit for RHEL 6 128 TB and how is this determined?

I'm studying for RHCSA and am confused by a statement I came across in some training material: There is no practical maximum RAM, as theoretically, you could run 128 TB of RAM on RHEL 6. But ...
7
votes
2answers
1k 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
1k views

What's the difference between a hard links and copied files?

RHEL 6 My understanding is that hard links include a copy of the original file and that I could delete a hard-linked file in one directory, and it would still exist in the other directory. If ...
6
votes
3answers
36k 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?
6
votes
1answer
5k views

Install g++ when having gcc (C only) — RH6

I have a RedHat 6 machine, which came with gcc but without g++. The gcc version is 4.4.4 20100726 (this is what I got from gcc --version). How can I get g++ working? Currently, the shell just returns ...
6
votes
2answers
3k 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
6
votes
4answers
804 views

Is there a pbuilder-like environment for RedHat?

I would like to know if is there any utility like Debian's pbuilder, to build RPM packages on RedHat using a clean environment (chroot). I've found mach which has support for something like this but ...
6
votes
2answers
11k views

Effect of entries in /etc/securetty

By default on RHEL 5.5 I have [deuberger@saleen trunk]$ sudo cat /etc/securetty console vc/1 vc/2 vc/3 vc/4 vc/5 vc/6 vc/7 vc/8 vc/9 vc/10 vc/11 tty1 tty2 tty3 tty4 tty5 tty6 tty7 tty8 tty9 tty10 ...
6
votes
3answers
1k views

What roles do DAC (file permissions), ACL and MAC (SELinux) play in Linux file security?

I need some clarification/confirmation/elaboration on the different roles DAC, ACL and MAC play in Linux file security. After some research from the documentation, this is my understanding of the ...
6
votes
1answer
586 views

Are Debian- and RedHat-style repositories compromised by Heartbleed OpenSSL bug?

The Heartbleed exploit (CVE-2014-0160) makes SSL connections using OpenSSL vulnerable to private key leakage. Does it mean that official update channels in RHEL/CentOS/etc. and Debian/Ubuntu shall be ...
6
votes
3answers
1k views

Installing Git, Curl, and Expat from Source

I have a RHEL 6.4 VM provisioned by my companies internal KVM. We are having some trouble using yum (Cannot retrieve repository metadata, which Ive confirmed in this case is peculiar to my company's ...
6
votes
2answers
483 views

How to choose LUKS encryption when installing RHEL 6?

With the default RHEL 6 installer, how can I choose the LUKS encryption? Afaik if I prepare the disk like cryptsetup luksFormat -c cast5-cbc-plain -s 128 /dev/$DEVICE could be the "fastest" ...
6
votes
1answer
2k views

Why does redirection (>) not work sometimes but appending (>>) does?

While studying for the RHCE, I came across a situation where stdin redirection does not work in bash: # file /tmp/users.txt /tmp/users.txt: cannot open `/tmp/users.txt' (No such file or directory) ...
6
votes
1answer
791 views

force re-negotiation of PCIe speed on Linux

I'm working with PCIe Gen 3 cards and from time to time they seem to fall back to PCIe 1 or 2 speeds (according to lspci and also observed by the throughput). When rebooting/power cycling the machine ...
6
votes
1answer
454 views

Why does `man -k cron` say `vixie-cron (rpm)` for some results, and how do I read those pages?

I'm trying to find out some details regarding cron and /etc/cron.d/ on a RedHat system. Ironically, my answer is viewable within the vixie-cron-*.src.rpm for this package, but the the man pages for ...
6
votes
1answer
290 views

Mailman / Postfix Configuration Assistance

I am writing for some help regarding Postfix configuration. I cannot seem to get Postfix configured properly to transfer mail to the mailing list installed on the same server. I followed many steps ...
5
votes
2answers
3k views

Difference between >> and >\> operators?

RHEL 6 Is there a difference between the >> and >\> operators? I read the following blurb in a RHEL training book: "You can add standard output to the end of an existing file with a ...
5
votes
5answers
5k views

Does AIX really beat Red Hat Enterprise Linux?

Our company plan to upgrade our servers, and at the same, we would use AIX over Red Hat Enterprise Linux. I asked my boss the reason of choosing AIX, he said it is because AIX is more powerful. I ...