Just use pdfimages: Change yourpdf.pdf to the name of your pdf output-name is the name format (eg. output-name01.jpg output-name02.jpg) is how the files will be named if you use "output-name". Change as needed. pdfimages -all yourpdf.pdf output-name After that you will have extracted all of the images. You can also just run the command with -list and see all of the images contained within the pdf lik........

Just export these variables: export http_proxy="socks5://127.0.0.1:1234" export https_proxy="socks5://127.0.0.1:1234" The above example uses a socks 5 proxy at localhost and port 1234. This is a great way to improve performance of some activities for things like package installation, especially if your routing is not ideal to the repos.........

Do you have a PDF that was too large after merging using convert / ImageMagick? Use gs or ghostscript as below, specify the output file and also the input file. In the example below the output file is "outputfile-resized.pdf" and the input file is "original-pdf.pdf". Change the input file to the name of your pdf gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/prepress -dNOPAUSE -dQUIET -dBATCH -sOutputFile=outputfile........

In a lot of distros, vdpau which accelerates video through the GPUis often not installed even in recent distros. This will result in Firefox with Youtube dropping frames when you check the "Stats for Nerds" and to the eye as jerky or slower video playback due to the dropped frames. Some sites will say that because you are watching VP09 that there is no GPU support, but with vdpau installed and enabled, many GPUs will still be able to use hardware decoding for 4K........

If you are running a local DNS server like named/bind and don't want to use the ISPsupplied DNS servers that are announced via a DHCP request (using dhclient) then the solution is simple. The reason should be obvious, but normally running your own DNS server will provide a more reliable, and fast DNS response and you won't have to worry about filtering as much (unless your upstream filters or proxies outgoing DNS requests). Edit /etc/dhcp/dhclient.conf........

If you get this error, it is often because you have configured Apache with modules that weren't actually installed. Eg. you try to load the PHPmodule but didn't actually install the apache2 php module, so the server can't start. In general, this error can often be caused by issues with problematic modules and/or Apache being configured for modules that have not actually be installed (eg. libapache2-mod-php) is missing. The above results in this less than obv........

This should work for most console ports of other manufacturers too. It is a quick and simple method for emegencies or deploying a few appliances/devices in a non-standard environment or small environment. However, if this is a route thing, or the equipment is not physically close to you, it would be best to use some sort of "Terminal" server which is an IP connected switch with several serial ports built-in for this purpose. Normally they accessible by web/........

Let's say you have a directory /mnt/raid which has files and directories inside it, but nothing is mounted to it. Then you mount a block device such as /dev/sdh to /mnt/raid Even though /mnt/raid has files and directories there, you can only see the mounted contents of /mnt/raid. How do we access the original contents? Just do a bind mount of the root filesystem to another location. mkdir /bindmount mount --bind / /b........

The issue is when you need to echo something as root/sudo, that it doesn't work. You can never do a sudo echo to an output file as you'd expect. Take an example to clear out wasted RAM buffers/cache like this: sudo echo 1 > /proc/sys/vm/drop_caches -bash: /proc/sys/vm/drop_caches: Permission denied The solution is to run tee as sudo/root What we do is echo 1, but then pipe it to the "tee" command as sudo........

By default if you create a private key for SSH, it will create something like .ssh/id_rsa Linux will always search for and offer this key when connecting to servers. If you put extra keys in your .ssh directory like id_rsa_realtechtalk.com, they will be ignored by default and NOT used or offered (you can verify this with ssh -v) and see it is not being offered. Here is how you add the extra SSH keys so they are all offered: #this gives........

If you plugin your phone to your computer and enable USB File Transfer/Allow on the phone side but the contents of your phone on the computer side are empty in the file manager, you probably don't have mtp-tools.MTP or media transfer protocol is the standard protocol that most phones use to communicate over USB to the computer. Just do this to fix it and get access to your files: apt install mtp-tools After that you should be a........

Sometimes due to your BIOS/EFI you may find that you have chosen "Energy Efficient" for your CPU which may effectively disable turbo mode. This is because "Energy Efficient" will often restrict or throttle your CPU to the base speed. This can impact nearly any CPU such as Intel's, AMDs, Opteron, Xeon etc... This is of course frustrating, for example if you have a CPU that is 2.0GHz base speed but turbo to 2.5GHz, you will never hit more than 2GHz.........

This article about migrating to a CentOS 7 /8 RAID mdadm array has a lot of info but I wanted to focus specifically on what newer versions of CentOS 7 require to boot mdadm and what changes are necessary on CentOS 7.8+ CentOS 7 / 8 mdadm RAID booting requirements This assumes you are chrooting into an existing install or using it to get a new deployment ready. However, these steps can........

A quick fix is to run this command: sudo brctl setageing br0 0 This causes the aging of the MAC address to time out immediately or in 0 seconds, which delete the entry frmo the FDB (Forwarding Database) and causes the error to go away. The default time is 300 seconds or 5 minutes. You can also add it under your br0 definition like this in /etc/network/interfaces to make it permanent and automatic: auto br........

Just edit your ~/.bashrc and add this at the very end: export PS1="realtechtalk.com" Then your prompt will look like this: bladeblox:uptime 08:47:14 up 48 min, 1 user, load average: 1.00, 1.07, 0.96 If you wanted a dollar sign at the end then you would change it like this: export PS1=&........

It really seems limited in that it can mainly give you the things you would see on the physical unit such as load etc.. wget https://downloads.sourceforge.net/project/apcupsd/apcupsd%20-%20Stable/3.14.14/apcupsd-3.14.14.tar.gz?r=https%3A%2F%2Fsourceforge.net%2Fprojects%2Fapcupsd%2Ffiles%2Flatest%2Fdownload&ts=1598115866 tar -zxvf apcupsd-3.14.14.tar.gz cd apcupsd-3.14.14 [root@somebox apcupsd-3.14.14]# ./conf........

function centos7 { release=`cat /etc/redhat-release|awk '{print $4}'|grep ^[7]` if [ "$release" != "" ]; then centos7='yes' fi } centos7 echo "$centos7" We create a function called "centos7" and then call it by just typing "centos7" We then access a variable that may be set........

Done on Centos 7.3 very important as clearly based on older guides it was a lot easier and more simpler! Hint do not use grub2-install! If you have trouble booting after this check this CentOS mdadm RAID booting/fixing guide. One huge caveat if you are an oldschool user or sysadmin who has avoided UEFIbooting The nor........

service named status rndc: connect failed: 127.0.0.1#953: connection refused named (pid 10557) is running... This issue is normally caused by a permissions issue where named doesn't have the permissions to read the rndc.key. Check /var/log/messages: Jan 4 17:06:22 storagebox named[10753]: none:0: open: /etc/rndc.key: permission denied Jan 4 17:06:22 storagebox named[10........

# yum -y install qemu-kvm Loaded plugins: fastestmirror Setting up Install Process Loading mirror speeds from cached hostfile * base: mirror.lzu.edu.cn * elrepo: ftp.utexas.edu * epel: ftp.jaist.ac.jp * extras: mirrors.aliyun.com * openvz-kernel-rhel6: mirror.fdcservers.net * openvz-utils: mirror.fdcservers.net * updates: mirrors.nwsuaf.edu.cn Resolving Dependencies........

cc: Internal error: Killed (program cc1) Please submit a full bug report. See for instructions. make: *** [ext/fileinfo/libmagic/apprentice.lo] Error 1 make: *** Waiting for unfinished jobs.... Stopping crond: ........

This is a handy link and list of all the relevant Directadmin log files and related servers. http://help.directadmin.com/item.php?id=11 DirectAdmin: /var/log/directadmin/error.log /var/log/directadmin/errortaskq.log /var/log/directadmin/system.log /var/log/directadmin/security.log Apache:........

************************************* * * * All parts have been installed * *........

I had a system running a 128MB live CD image with 2.8 gigs of available RAM and the OOM kernel killer went crazy when using dd for more than 8 minutes and kept killing everything. I've read that this is due to a low-memory issue and paging in the kernel and 32-bit systems with lots of RAM. I even enabled swapspace on my LiveCD and the issue happened 25 minutes into dd rather than 8 minutes, so what gives? Also no swap space was ever used! cat /proc/s........

I like dd, although it only reads it, usually a read test of the entire disk will uncover if your hard drive is bad in some parts. This is a good thing to do at least once a month, a lot of times bizarre program behavior, laginess and crashing/unnmounting problems etc.. are due to a failing disc and SMART won't know it or indicate a problem: We must also remember there's never a guarantee, I've found that ever since we moved to larger and more platters per drive with 1TB drives........

I had one of these shipped and it was not recognized when plugged in, here's what a dead drive looks like (I assume it's teh circuit board which is dead): ata1: link is slow to respond, please be patient (ready=0) ata1: softreset failed (device not ready) ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300) ata1: link online but device misclassified, retrying ata1: link is slow to respond, please be patient (ready=0) ata1: softreset f........

http://apt.sw.be/redhat/el5/en/i386/test/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found Trying other mirror. Error: Cannot retrieve repository metadata (repomd.xml) for repository: rpmforge-testing. Please verify its path and try again Notice it is complaining about "rpmforge-testing", just disable it for now: Solution is to edit the repo: vi /etc/yum.repos.d/rpmforge-testing.repo........

This function and others may not work with the stock PHPinstall on Centos/CPanel: Fatal error: Call to > undefined function imagecreatefromjpeg() Even with libjpeg-devel installed it won't work because PHP was not compiled with jpeg support, so we have to do the dirty work ourselves :) Here is the command/yum's I did to install missing libraries for PHP that configure will complain about (yes it is a one by one process). yum install bzip2-........

Seagate Inventory/Firmware Check I heard about this issue a long time ago but never looked into it. I figured I wasn't affected since my 500GB drives were running for so long. I've been using Seagate's since 2002 and to this day all of the drives I have are alive from Seagate. *Update the bad news is that I realize one of my 500GB's is about to die, it's not even a year old, but is also not affected by the recall according to Seagate! Seagate Inventory/Firm........

PHP cannot access /usr/bin/opensslI have verified the username that runs the process is able to access /usr/bin/openssl and it does exist but the PHP script is saying it doesn't exist: [code:1:1fd0f3abbe] if (!file_exists($OPENSSL)) { //echo "ERROR: OPENSSL $OPENSSL not foundn"; }[/code:1:1fd0f3abbe] I don't get itI can clearly see the contents of /usr/bin by using the PHP system fu........

Setup Static IP Address ONBOOTAssuming you are using eth0 Note this will work for any version of CentOS and basically any version of Redhat Linux or Redhat based distribution. You would need to create a new file [code:1:02f8d34c30] /etc/sysconfig/network-scripts/ifcfg-eth0:0[/code:1:02f8d34c30] DEVICE=eth0:0 the ":0" at the end specifies alias 0 we could actually change this to ":99" or "........

Updated to Version 3.8 and can't loginSSHD accepts my password but then hangs at "Last login: Wed Sep 13 21:30:02 2006 from" This occurred during a yum update after upgrading my release, installing the new kernel and rebooting. I got kicked out of sshd after seeing the following during yum update: telnet 100 % done 85/476 tux 100 % done 86/476 ntsysv 100 % done 87/476 rpmdb-redhat 94 % done 88/476........

Updating yum repos for DAG /etc/yum.repos.dIn /etc/yum.repos.d [quote:96456b2ab9]Create any file such as "CentOS-Dag.repo" in /etc/yum.repos.d[/quote:96456b2ab9] Add the following to the above file: [code:1:96456b2ab9] [dag] name=Dag RPM Repository For Red Hat Enterprise Linux baseurl=http://dag.atrpms.net/redhat/el$releasever/en/$basearch/dag/ http://dag.freshrpms.net/redhat/e........

Shortcut/Easiest Way To Create A Self-Signed Key: openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key Using the above, you instantly create a self-signed certificate valid for 1530 days and you can simply skip to step #5.) below. If You Need a Real SSLCertificate (eg. Equifax/Openssl) then you need to create a CSR request (you'll need to follow Steps 1.) and 2.) in order to create the CSR. You then upload the CSR Certi........

It's a bit of a pain that many basic third party tools that aren't put of the main Centos/RHEL repositories are not available unless you compile them or install the RPMForge Repo. *Updated 08/29 with new download location changed from apt.sw.be to rpmforge.sw.be Here's a quick, simple/cut&paste way to do it: wget http://rpmforge.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0.5.1-1.el5.rf.i386.rpm rpm -i rpmforge........

In those 4 simple commands you can setup mutual key exchange between two sshservers by using a single login shell session and single window. *Just change the IP address examples of (10.10.0.2) to the target of your mutual key exchange. It doesn't matter if the server is on a LANor WAN(well unless the server is behind a firewall and you cannot SSHinto it).........

For some reason Ikeep getting this error when trying to run a sudo command eg: sudo -u someuser somecommand sudo: Error dropping capabilities, aborting My version of sudo is:sudo-1.6.9p17-3.el5_3.1 and I've heard that version 1.7 fixes everything. The only thing is yum does not think sudo has any update. Iguess the new version has not been committed to the RPM repository yet. This is really a huge and ann........

This is something that annoys a lot of people, fortunately the Redhat style OS's are the most simple in this respect. I disagree that Debian's way makes sense, it is more of a hackish approach in how they implement iptables. Anyway, for those who are using Redhat/Centos style OS's it is very simple. Set your rules from the shell/command prompt and to save the iptables firewall rules so they are remember/loaded on boot just run this command: service iptables........

There's a lot of outdated information and confusion for system administrator's out there. One annoying task for many an Administrator has been backing up data in Linux. You don't need any GUI tools such as K3B or GnomeBaker. Both are excellent tools but for veteran command line users working remotely, using the keyboard is a great and possibly automated way to save yourself pain and hassle. At a later date we'll cover how scripting can automatically backup certain........