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Troubleshooting Unix / Linux Servers

Troubleshooting tips about Linux, *BSD, UNIX, Apple OS X, programming and MS-Windows servers and desktop systems ( rss feed ).

HowTo: Speedup ping and traceroute Command Responses under Linux / Unix

The following question was asked in the Unix networking exam:

     How do you speed up ping and traceroute command responses under Unix or Linux operating systems?

How can I speed up my ping or traceroute commands on a Linux?
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Debian / Ubuntu: Fatal error: Python.h: No such file or Directory

I am trying to install 3rd party python apps using pip command and getting the following error:

gcc -pthread -fno-strict-aliasing -fwrapv -Wall -Wstrict-prototypes -fPIC -std=c99 -O3 -fomit-frame-pointer -Isrc/ -I/usr/include/python2.7 -c src/MD2.c -o build/temp.linux-x86_64-2.7/src/MD2.o

src/MD2.c:31:20: fatal error: Python.h: No such file or directory

compilation terminated.

error: command 'gcc' failed with exit status 1

Where can I find Python.h file and how do I fix this problem under Debian or Ubuntu Linux sever based system?
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HowTo: Check Swap Usage in Linux

How do I check swap (paging) usage under Linux operating systems using command bash/ksh line options?
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One of my php script called setoptions.php is hosted on my new vps server. However, it is not working so I setup php error log as described here and, and I see the following warning repeated in my log file:

PHP Warning: fread(): Length parameter must be greater than 0 in /var/www/html/scripts/setoptions.php on line 311

The line no # 311 is as follows in my php script:
$fname = 'myappconfig.php';
$content = fread($fhandle,filesize($fname));

How do I fix this problem under Unix/Apache/php5 server?
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Linux Command To Find SATA Link Speed Such as 1.5 / 3.0 / 6.0 Gbps [ Hard Disk ]

How do I find out my SATA link speed? How do I make sure my sata hard disk is working at 6Gbps speed and how do I verify this on a Linux server running on HP or IBM amd64 hardware?
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Linux: Find Out What’s Using Up All Virtual Memory

How do I list or display all processes, executables, and shared libraries that are using up all virtual memory under Debian or Ubuntu Linux server for troubleshooting purpose?
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PHP: Require_once(): Unable To Allocate Memory For Pool Error and Solution

I‘m running PHP version 5.3.3 on CentOS / RHEL 6.x with APC php-pecl-apc-3.1.9. However, I’m getting the following warnings in my php server log file:

[01-Jul-2012 10:50:49] PHP Warning: require_once(): Unable to allocate memory for pool. in /var/www/html/includes/admin.php on line 57
[18-Jul-2012 17:00:08] PHP Warning: include_once(): Unable to allocate memory for pool. in //var/www/html/includes/xmlrpc.php on line 55
[18-Jul-2012 17:00:40] PHP Warning: require(): Unable to allocate memory for pool. in /var/www/html/includes/geshi.php on line 2307

How do I fix these php warnings?
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Could not chdir to home directory /root: No such file or directory Error and Solution

When I ssh into my server and login as t root user and I’m getting the following error on screen:

Could not chdir to home directory /root: No such file or directory

How do I fix this error under CentOS or Debian Linux server?
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I‘m trying to run an application and getting the following error on screen:

error while loading shared libraries: libgobject-2.0.so.0

How do I fix this problem under Debian or Ubuntu 64 bit (amd64) Linux?
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Linux Nvidia: NVRM: GPU at 0000:01:00.0 Has Fallen Off The Bus Error and Solution

I‘m using NVIDIA UNIX x86_64 Kernel Module version (driver) 280.13 under Debian 64 bit Linux with Linux kernel 2.6.32-5-amd64 x86_64. However, I’m getting the following errors in my /var/log/messages file

Feb 13 05:53:39 wks01 kernel: [26652.425207] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
Feb 14 03:59:14 wks01 kernel: [39846.244283] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
Feb 17 04:47:32 wks01 kernel: [35237.485871] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
Feb 18 06:53:19 wks01 kernel: [49298.937949] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
Feb 19 06:14:01 wks01 kernel: [28508.567838] NVRM: GPU at 0000:01:00.0 has fallen off the bus.

This error occurs randomly and my laptop goes in hard freez mode. The hard reboot is the only way to recover from complete freeze of my Dell M6500 Debian Linux based laptop. How do I fix this problem?
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