System Notes Org

Here is a quick example of how to use BCC in Yahoo Mail Classic. The idea is similar in many different email programs. Easy Two Step Process There are two simple steps to help your recipients avoid getting flooded with spam. 1.) Enable the Bcc feature 2.) Use "Bcc:" instead of "To:" whenever sending mail to multiple recipients. Screen Shots Step 1.) Find and Enable the Bcc feature Step 2.) Use Bcc: That's all there is to it! You'll be saving your friends from tons of unwanted emails by keeping their email addresses private. For more details on why BCC is important, please see this article: http://systemnotesorg.blogspot.com/2008/02/bcc-howto.html

I came up with some flashcards based on commonly used redhat linux commands. Here is my working draft. RHCE -Flash-Cards These notes should be helpful to anyone working on Redhat Enterprise Linux (RHEL), or preparing for the RHCE exam. My RHCE Study Guide was hugely popular, but unfortunately it had some potential copyright issues. This group of flashcards has also been released as a quick study guide, or cheat sheet, and contains much of the same original study guide material, but with all proprietary information removed. This 3-page guide is listed as RHCE Flash Cards (condensed version) How These Slides Were Created These slides were produced using OpenOffice.org Impress. Created Slides Saved as html Copied contents of html between body tags to .page files. Used a bash shell script with sed, and awk to get the files to appear properly for webgen. See script here— html2page.html Ran webgen on the directory to generate .html Also .pdf files were saved from Openoffice.org Wri...

perl -MCPAN -e shell I always seem to forget this simple syntax, so I thought it would be good to post it where I can find it. Where else, my blog -- by the way, this is another excellent use for blogs. Not only do we publish information for others to find, but occasionally a blog is the best place to put frequently accessed info that the author may need. At least I know the source is reliable. :-) How do I install a module from CPAN? The easiest way is to have a module also named CPAN do it for you. This module comes with perl version 5.004 and later. To get a cpan shell, try either cpan: Linux:   $ cpan Windows:  C:\>cpan or the more complete command: $perl -MCPAN -e shell Terminal does not support AddHistory. cpan shell -- CPAN exploration and modules installation (v1.7601) ReadLine support available (try 'install Bundle::CPAN') cpan> The first time the command runs, it will prompt for a series of configuration questions. Now, within the...

Get your Friends to use BCC Send this link, or the contents of this post, to all your contacts, ...using BCC, of course. When you receive a forwarded message, reply with a simple message, such as one or more of the following: "Please don't forward any email to me without using BCC. " "Please don't put my email address in the To or CC fields of messages being sent to people I don't know!" "Please protect email addresses as you would unlisted phone numbers." "Please don't forward any email to me with my email address in the To: or CC: fields." "This is how spam and viruses get spread. See this article for more details -- BCC HOWTO " What is BCC? BCC (Blind Carbon Copy), is the practice of sending an e-mail to multiple recipients without disclosing the complete list of recipients. Unlike addresses in the To: or CC: fields, addresses in the BCC: field cannot be seen by other recipients. Reasons to use B...

Every once in a while, I like to try a few live CD's to see how the distros are progressing. I am happy to report that Ubuntu is getting more usable with each release. I titled this "Notes from..", rather than "Notes about", because I was able to work within a live CD session, and save my files. I admit I wasn't very impressed with the first version of Ubuntu I looked at. That was version 4.1, which I got in live CD format from a local linux user group meeting. After realizing that I couldn't read my NTFS partitions, I played a few games, and quickly lost interest. Also, I had a slower laptop at the time, and having the os frequently read from the CDROM made the experience slightly annoying. Now with a faster CDROM drive, and all the updates, the system is quite pleasant to use. Getting Started Using a boot CD is quite easy, and does not require anything to be installed to the hard drive. The entire operating system can be booted from a CD, and run...

Did you ever wonder if there was an easy way to send an example file for someone to look at, but still keep your private information safe? Sure you can use a sed, or perl one-liner, as I discussed: using-bash-and-sed-to-modify-text-file.html , but why not use search and replace in vi / vim before publishing your info? That way you can see exactly what you are changing. Remember, while vim is installed by default on most Linux distros, is also available for Windows, and it is free -- http://www.vim.org Suppose you have part of a log file, or nmap output that contains real hostnames, a real domain name, and real IP addresses. You want someone to help you troubleshoot something, but you don't what to give the real info for everyone to see. Start with the info in a text file, such as this: Host realhost-1.realdomain.com (192.168.0.54) appears to be up. Host realhost-2.realdomain.com (192.168.0.55) appears to be up. Host realhost-3.realdomain.com (192.168.0.56) appears to be up. Host...

Sure, you can now download music from the iTunes store without DRM but that doesn't mean you should just willy nilly start sharing that music with your friends. For one thing, it's illegal. For another, your account information is embedded into that m4a music file. Don't believe me? Try this yourself. The site is mostly for Mac users, but the strings command works in linux, and cygwin for Windows. This link has interesting comments as well. read more | digg story

VNC is an excellent way to remote control linux and Windows machines. Here is a description, and links to the programs. Blogger Digest: Using VNC And Redhat Linux x11vnc official site Real VNC Server official site TightVNC TightVNC software UltraVNC UltraVNC software

These RCHE study notes were designed to be brief reminders of what you should already be familiar with. This topic covers HTTP server configuration. One thing to be aware of when working with Apache and the 2.6 kernel is SELinux. Overview of SELinux SELinux, is a Mandatory Access Control (MAC) security system for Linux based on the domain-type model. It was written by the NSA ( http://www.nsa.gov/selinux/ ) and is comprised of a kernel module (included in all 2.6 kernels), patches to certain security related applications, and a security policy. More info: http://www.redhat.com/magazine/001nov04/features/selinux/ Study Notes Here are the brief steps from my RHCE study guide to help you remember the steps to configure a virtual host, and configure permissions. * HTTP/HTTPS install httpd, check context with ls -Z   Q: Create a virtual host www1.example.com w/ subdirectory /var/www/html/www1   A:    1) install httpd, modify /etc/httpd/conf/httpd.conf file  ...

About P2P P2P software is free, and legal to install and use, but it does make sharing of copyrighted material easy to do, and that is not legal. Are people still using P2P software after Napster got shut down? Yes, they certainly are. Free music downloads? Free software? -- well be careful about copyrighted materials, but the technology is interesting nonetheless. One of the best ways to get a large file, such as a linux iso file, is to use bit torrent. Dangers What are the dangers, and inconveniences of using peer to peer file sharing software such as Limewire, eDonkey, Azureus, or Bittorrent? 1.) The content quality is only as good as how trustworthy the peers are 2.) Some content is copyrighted, and may be illegal to share or download on this type of network 3.) Content may contain viruses, trojans, and decoys 4.) Excessive traffic may cause your ISP to limit your bandwidth usage 5.) Some downloads may take days to complete 6.) There may be pornography disguised as something ...

In Linux, directories are not accessible until the device is mounted. This is usually done at startup by the mount command which uses the /etc/fstab file. Files that start with a dot "." are hidden, but not completely (you can do ls -a to see the files). An example is the ~/.bashrc file. You can also hide files in a directory name that starts with a dot, e.g. ~/.ssh Now for the real trick Entire directories can be hidden, simply by mounting another device on top of the directory. The original files will still be in tact, but not visible until the device is remounted. First, find a device that is available to mount (boot is nice, because it is usually small). $ mount /dev/hda1 on /boot type ext3 (rw) ... etc... Then make your stealth directory, copy files to it, and mount a directory over it. $ cd /mnt $ mkdir stealth $ touch /mnt/stealth/somefile.txt $ ls /mnt/stealth/ somefile.txt $ mount -t ext3 /dev/hda1 /mnt/stealth ls /mnt/stealth/ config-2....

Google has some excellent webmaster resources, and some fun and useful gadgets that can be quickly added to a website or blog. Just as with any good design, remember not to over do it. http://www.google.com/webmasters/gadgets/ Here is what Google says about their gadgets: ------------------------------------------------------------------------------ Enhance Your Own Website Add Google Gadgets to your webpage You can now use Google Gadgets to make your webpages even more interesting and useful to your visitors. For instance, you can add your city's current temperature or a quote of the day to your own page. Just pick the gadget you want from our directory of "Google Gadgets for your webpage," customize that gadget, and copy-and-paste the HTML into your page's source code. Then, reload to see the gadget on your page. Find gadgets for your webpage. ------------------------------------------------------------------------------ If you want to find something about cooking...

This is a very simple topic, but sometimes little tips can save you a lot of time. Windows & Linux First select the text, or item, or location to paste to: Copy = Ctrl-c, or From the "Edit" menu, select "Copy" Cut = Ctrl-x, or From the "Edit" menu, select "Cut" Paste = Ctrl-v, or From the "Edit" menu, select "Paste" You can copy and paste text, graphics, files, etc. In Windows, you can copy and paste files within Windows Explorer, or you can drag and drop them. Linux All of the above, plus: Copy = Select text with the mouse Paste = Click the middle mouse button vi If you want to copy and paste in vi, that's another topic. To copy a line in vi, type yy (yank line), and then p (paste after), or P (paste before). To copy a word, use yw (yank word). To copy five lines -- 5 yy, or five words -- 5 yw, or to paste something five times 5p. Here are some good tips on vi http://www.vim.org/tips/tip.php?tip_id=312 . By t...

IP Forwarding Effectively makes a Linux box act as a router Is usually used with two network interfaces (one internal, and one external) Can be used with firewall services and is often used for NAT Steps to Turn on IP Forwarding  1) Modify /etc/sysctl.conf      vi /etc/sysctl.conf      add this line:      inet.ipv4.ip_forward=1  2) Make the Change Active      sysctl -p  3) To View Current Settings:      sysctl -a | grep ipv4 More info can be found on the redhat site: https://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/security-guide/s1-firewall-ipt-fwd.html We'll leave firewall rules for another topic... rhce linux

This procedure assumes you have console access, and are authorized to make changes to accounts on the machine, including root. If you own the machine, you can boot into single user mode, and change the password, or create an account. If using grub (you should see a blue bootup screen), press "a", "space", "1", "enter" a 1 That will boot to single user mode. Then you can change the root password passwd Then reboot Ctrl-Alt-Del You should create user accounts other than root. Use the useradd command. useradd someone passwd someone rhce linux

Study notes for any exam are difficult enough to find, but RHCE material seems even more scarce. This article tells how to prepare for one of the objectives, which is configuration of an SMTP server. RHCE Study Notes I wrote up some study notes as I was preparing for the RCHE exam. Here are some quick notes based on the official RedHat objectives , labs, and possible questions I thought might be reasonable requests. SMTP Related Questions install sendmail, sendmail-cf, sendmail-doc (optional) Q: Configure mail server to accept internet email A: modify /etc/mail/sendmail.mc 1) cd /etc/mail 2) vi /etc/mail/sendmail.mc search for 127.0, put dnl at the front of the line 3) make or m4 sendmail.mc > sendmail.cf service sendmail restart Q: Mail alias A: modify /etc/aliases, run newaliases Q: Receive mail for DomainX.example.com A: modify sendmail mc as above, and add domain to /etc/mail/local-host-names ...

For Linux / Unix Follow as instructed For Windows Download cygwin from http://cygwin.com For instructions, see this article: http://systemnotesorg.blogspot.com/2007/04/use-cygwin-to-run-linux-on-windows.html Two Easy Steps for One-Liners e.g., you have a list of servers, and would like to do something, such as ping each one, or check their IP address. Here is a quick two-step process, with a one-line shell script that can be run from the command line. 1) Create a Text file, with one hostname per line 2) Run a for loop on the file $ cat servers.txt server01 server02 server03 $ for host in `cat servers.txt`;do host $host;done server01.example.com has address 10.10.10.10 server02.example.com has address 10.10.10.11 server03.example.com has address 10.10.10.12 $ If you want different output, you can use awk, but that's another topic. Notice a few things about this one line script. 1) Each command is separated by a semicolon ";" 2) The ba...

Yes, not only can you run Linux from a CD -- http://systemnotesorg.blogspot.com/2007/04/how-to-get-started-with-linux.html , but you can also install it in Windows, and run it as a Windows program. You get a standard linux bash shell, and even X, with a little configuration. What Is Cygwin? (from http://cygwin.com ) Cygwin is a Linux-like environment for Windows. It consists of two parts: A DLL (cygwin1.dll) which acts as a Linux API emulation layer providing substantial Linux API functionality. A collection of tools which provide Linux look and feel. The Cygwin DLL currently works with all recent, commercially released x86 32 bit and 64 bit versions of Windows, with the exception of Windows CE. Note that the official support for Windows 95, Windows 98, and Windows Me will be discontinued with the next major version (1.7.0) of Cygwin. What Isn't Cygwin? Cygwin is not a way to run native linux apps on Windows. You have to rebuild your application from source if you want it to r...

Have you always wanted to find out more about linux, but were not sure where to start? Here is a little information on where to find, and how to run and / or install a linux distribution. What is Linux? Linux is the kernel, or core part of an operating system that is free from any software licenses. Free to download, and install on as many machines as you like. Here's an explanation from http://www.gnu.org/ The GNU Operating System - Free as in Freedom What is the GNU project? The GNU Project was launched in 1984 to develop a complete Unix-like operating system which is free software: the GNU system. Variants of the GNU operating system, which use the kernel called Linux, are now widely used; though these systems are often referred to as "Linux", they are more accurately called GNU/Linux systems. GNU is a recursive acronym for "GNU's Not Unix"; it is pronounced guh-noo, approximately like canoe. Trying Linux First, you may not have known that ...

...and maybe make some money. An article I posted on http://systemnotesorg.blogspot.com discusses how to get more traffic to your site. http://systemnotesorg.blogspot.com/2007/04/search-engine-optimization.html Now let's concentrate on how to set up a blog. With blogger, you don't have to know any html, but if you do, it helps. Getting Started First go to http://www.blogger.com and create a blog. If you already have a gmail account, you have completed the first step. It is really simple, and they walk you through it. Think of a name, and what you would like to write about. O.K., so you have a blog, now what? There is a book title that should help you keep on topic -- " No One Cares What You Had for Lunch " Then start posting. You can set up your blog to receive email, so posting is very easy. Just send an email to the address you set up under settings / email. Making money Well, keep posting something useful, but If you want to make money, don't wa...