Greatest Hits

39
votes
4answers
46k views

What does “Warning: untrusted X11 forwarding setup failed: xauth key data not generated” mean when ssh'ing with -X?

When I use ssh -X on my Mac (running OS X 10.6.7) to connect to my Ubuntu (11.04) box, I get the following warning: Warning: untrusted X11 forwarding setup failed: xauth key data not generated ...
24
votes
4answers
45k views

System process (PID 4) constantly accessing the hard disk

Recently I noticed some of our machines are getting sluggish, mainly after boot-up. Using the Resource Monitor I detected excessive disk access from the system process with PID 4. Following some tips, ...
7
votes
10answers
50k views

Exchange 2010 and Outlook 2010 requesting password every time it starts

I have one Exchange 2010 server which is fully updated, the clients are running Outlook 2010 but some users are getting a prompt for credentials every time they open Outlook. I have checked for ...
9
votes
1answer
63k views

What is a SQL Server instance?

When I install SQL Server 2008 Express in prompts me to create an instance and aborts if I don't. Then I see that information in an entry in Sql Server Configuration Manager on SQL Server Services. ...
50
votes
4answers
43k views

How to run a command multiple times?

Is there a way to run a command (e.g. ps aux|grep someprocess) for n times? Something like: run -n 10 'ps aux|grep someprocess' I want to use it interactively, please do not post scripts. ...
69
32
votes
9answers
51k views

How do I get apt-get to ignore some dependencies?

How do I make apt-get ignore some dependencies? For example, I wanted to install mailx so I can use it to send email from cron scripts/report-generating tools. However, installing mailx also installs ...
2
votes
2answers
16k views

how to fix corrupt, not cleanly closed and upgrade needing tables in mysql

When I restart mysql server in Debian, I always have the below messages. How to make the messages disappear or fix the problem/corrupted tables? debian:~# /etc/init.d/mysql restart Stopping MySQL ...
15
votes
4answers
58k views

How do you wait for an exe to complete in batch file?

I'm trying to create a script to execute an exe on shutdown in order to install sp1. my script goes something like (not actual bat script). If installed GOTO END Install.exe END: My problem is ...
32
votes
2answers
37k views

How to get the url of the current svn repo?

I have 2 svn checkouts that someone setup for me. Now I need to check these same files on another computer, but since I didn't check them out initially I don't know the urls to use when running the ...
27
votes
8answers
64k views

How to display certain lines from a text file in Linux?

I guess everyone knows the useful Linux cmd line utilities head and tail. Head allows you to print the first X lines of a file, tail does the same but prints the end of the file. What is a good ...
9
votes
2answers
40k views

How do i find out what my IP Address of my MySQL host is?

I have a free domain running at x10hosting (x10.bz), and I want to find out the IP Address of my MySQL host for it, so I can contact the MySQL database from another host. I've already added that host ...
18
votes
6answers
63k views

What is the value of JAVA_HOME for CentOS?

I have install java through yum on CentOS, however another java programme needs to know what the JAVA_HOME environmental variable is. I know all about setting environmental variables, but what do I ...
25
votes
1answer
51k views

How do I change the privileges for MySQL user that is already created?

I understand how to create a new user with privileges, but what is the correct way to change privileges for users that are already created? We are running a DB audit and some of the users have way ...
72
10
votes
2answers
57k views

How to test a LDAP connection from a client

How to check the LDAP connection from a client to server. I'm working on the LDAP authentication and this client desktop needs to authenticate via a LDAP server. I can SSH to the LDAP server using ...
72
votes
1answer
48k views

What is a challenge password?

I'm setting up SSL on an Ubuntu server. One of fields it asks for as part of setting up the CSR is a "challenge password". What is that? The default is blank. Do I need to enter one?
63
34
votes
6answers
60k views

How to send emails and avoid them being classified as spam

This is a canonical question about how to handle email sent from your server being misclassified as spam. For additional information you may find these similar questions helpful: Best ...
17
votes
7answers
67k views

Nginx + php-fpm “504 Gateway Time-out” error with almost zero load (on a test-server)

After debugging for 6-hours - I am giving this up :| We have a nginx+php-fpm+mysql in LAN with almost 100 wordpress (created and used by different designers/developers all working on test wordpres ...
48
votes
5answers
83k views

How to start/stop/restart launchd services from the command line?

How do I restart, say for example my httpd or afpd, running any Mac OS X >= 10.5 (Leopard-), without having to use the GUI and go to System Preferences -> Sharing and unchecking/checking "Web ...
6
votes
7answers
46k views

What is an edge server / router / device?

What is an edge server? We see some references to them, but we never see a definition.
6
votes
6answers
12k views

What is a recommended way to patch the Shellshock Bash bug on an unsupported Ubuntu server?

I maintain an out-of-support Ubuntu 12.10 (Quantal Quetzal) server (don't ask me why, please), and we need to patch the Shellshock Bash security bug. As upgrades are not available anymore, what ...
44
votes
8answers
58k views

How can I monitor hard disk load on linux

Is there a good command line utility to monitor hard disk load on linux? Something like top but then monitoring disk activity i.s.o. cpu usage. More specifically, I suspect that for some (heavy load) ...
11
votes
4answers
39k views

Nginx 1 FastCGI sent in stderr: “Primary script unknown”

My first time using Nginx, but I am more than familiar with Apache and Linux. I am using an existing project and when ever I am trying to see the index.php I get a 404 File not found. Here is the ...
22
votes
6answers
56k views

what are named and default instance?

what are named and default instance? what is the difference between them? why they are used?
16
votes
9answers
69k views

How do I make Linux recognize a new SATA /dev/sda drive I hot swapped in without rebooting?

Hot swapping out a failed SATA /dev/sda drive worked fine, but when I went to swap in a new drive, it wasn't recognized: [root@fs-2 ~]# tail -18 /var/log/messages May 5 16:54:35 fs-2 kernel: ata1: ...
19
votes
4answers
68k views

connect() failed (111: Connection refused) while connecting to upstream

I'm experiencing 502 gateway errors when accessing a PHP file in a directory (http://domain.com/dev/index.php), the logs simply says this: 2011/09/30 23:47:54 [error] 31160#0: *35 connect() failed ...
32
votes
4answers
43k views

How do I grep through binary files that look like text?

I have binary files that should be text (they're exported logs), but I can't open it with less (it looks ugly - it looks like a binary file). I found that I could open it with vi and I can cat it ...
68
votes
17answers
47k views

How can I get the size of an Amazon S3 bucket?

I'd like to graph the size (in bytes, and # of items) of an Amazon S3 bucket and am looking for an efficient way to get the data. The s3cmd tools provide a way to get the total file size using s3cmd ...
13
votes
4answers
69k views

What causes duplicate ACK records?

We're reviewing Wireshark captures from a few client machines that are showing multiple duplicate ACK records which then triggers retransmit and out-of-sequence packets. These are shown in the ...
15
votes
4answers
70k views

What's the maximum number of wifi connections for a single WiFi router?

We've got a Draytek 2829VN Wifi router and I'm wondering how many concurrent connections I should expect a router of this kind to cope with? We are looking to connect 60 iPads! I'd also be ...
6
votes
7answers
62k views

How do I permanently change the hostname on Solaris 10?

I want to permanently change the hostname on a Solaris box. How do I do that?
65
95
votes
2answers
36k views

How can I see which flags Nginx was compiled with?

How can I check what modules have been added to an nginx installation?
72
6
votes
2answers
49k views

What is the difference between RDIMM vs UDIMM

I don't quite understand the differences between the two besides the obvious price differences. What does each offer over the other?
7
votes
4answers
73k views

How to check if hardware RAID is configured?

I have several servers running Windows 2008 and Red Hat 5 that are capable of hardware RAID. How do I check that hardware RAID is configured?
17
votes
3answers
39k views

how do you create an ssh key for another user?

I'm trying to create an ssh key for another user. I'm logged in as root. Can I just edit the files generated by ssh-keygen and change root to the user I want?
46
votes
5answers
53k views

How to setup passwordless `sudo` on Linux?

How can passwordless sudo access be setup on either RHEL (Fedora, CentOS, etc) or Ubuntu distributions? (If it's the same across distros, that's even better!) Setting: personal and/or lab/training ...
17
votes
4answers
48k views

Prevent Windows Server 2012 from forcing a reboot after updates

I have a domain controller with Windows Server 2012 on it. After updates, the server does not reboot immediately. However if I remote into the server I will be presented with a countdown for a reboot. ...
16
votes
3answers
74k views

For Loop counting from 1 to n in a windows bat script

I need to run a windows command n times within a bat script file. I know how to do this in various programming languages but cannot manage to get it right on the windows command line :-( I would ...
125
votes
4answers
38k views

LVM dangers and caveats

I have recently started using LVM on some servers for hard drives larger than 1 TB. They're useful, expandable and quite easy to install. However, I could not find any data about the dangers and ...
10
votes
5answers
51k views

How to install mcrypt for PHP 5.3.3 on CentOS 5.7 64 bit?

I installed php 5.3 and some modules using yum install php53-{module-name} But mcrypt did not work. I searched like this: yum list php* | grep mcry The only package that came up was ...
43
votes
7answers
63k views

Should I use tap or tun for openvpn?

What are the differences between using dev tap and dev tun for openvpn? I know the different modes cannot inter-operate. What is the technical differences, other then just layer 2 vs 3 operation. ...
5
votes
2answers
32k views

List All Groups and Their Members with PowerShell on Win2008r2

I am new to powershell, but I've been reading manuals and practiced a little bit. My objective is to List all users in all Security Groups under specified path. I have found the way to do it: ...
24
votes
6answers
87k views

add new user with root access in Linux

I want to add new user and have/grant that new user to have all the root access, how can I do that ? I did sudo adduser --system testuser but this is not working as I expected. Thanks for help.
14
votes
1answer
72k views

Where/how does Windows store the data in the event logs?

We run some financial systems that log error messages to the system logs. I need to find out if we can clean these error messages from a PCI DSS point of view. I am specificaly interested in the ...
35
votes
5answers
40k views

When does /tmp get cleared?

I'm taking to putting various files in /tmp, and I wondered what the rules on deleting them are? I'm imagining it's different for different distributions, and I'm particularly interested in Ubuntu ...
31
votes
7answers
55k views

How do I check the postfix queue size?

What's the postfix equivalent to sendmail -bp?
66
9
votes
5answers
83k views

Can you use a USB hard drive in ESXI?

I know that you can install ESXi 4.0 on a thumbdrive, but I was wondering if you could plug in an external harddrive to give extra storage to one of your VMs? We run a fileserver inside of ESXi that ...
9
votes
4answers
11k views

Can not update Bash on Debian 6.0 (Squeeze)

I can not update Bash on a Debian 6.0 (Squeeze) server to get rid of the discovered vulnerability: bash --version GNU bash, version 4.1.5(1)-release (x86_64-pc-linux-gnu) apt-get update apt-get ...
13
votes
7answers
53k views

Powershell: How do I query pwdLastSet and have it make sense?

I need to get the last password change for a group of account in an Active Directory security group, and I feel like this is something PowerShell should be good at. Right now, I'm already stuck at ...
15
votes
4answers
67k views

Is it possible to mount/unmount a physical hard drive in Windows XP?

Is it possible to mount/unmount a physical hard drive in Windows XP? Ideally, I'd like to be able to do this from the command line so that I could have batch files to do it, ie: mount.cmd unmount.cmd ...
183
votes
13answers
67k views

Any benefit or detriment from removing a pagefile on an 8GB RAM machine?

I'm running Windows 7 on a dual core, x64 AMD with 8GB RAM. Do I even need a pagefile? Will removing it help or hurt performance? Would it make a difference if this is a server or a desktop? Does ...