Sandra Henry-Stocker

Sandra Henry-Stocker

Member since: June 2008


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Sandra Henry-Stocker has been administering Unix systems for more than 25 years. She describes herself as "USL" (Unix as a second language) but remembers enough English to write books and buy groceries. She currently works for TeleCommunication Systems -- a company that builds innovative technologies to make critical connections happen -- where no one else necessarily shares any of her opinions. Send comments and suggestions to

Areas of Interest: Networking, Software, Virtualization, Security, unix


  • Malware represents one of the greatest threats that organizations face today and IT departments are coming to understand that their AV tools can only do so much to protect them. When malware is discovered on their systems, they want to know what it might have done, if the threat is still ongoing, and what they might have lost to the infection. Answers can be very tough to find, but reverse engineering the malware might just be the way to provide them.

    1 year 22 weeks ago

  • Don't throw up your hands if your boss won't buy you Tripwire and a modern debugger. There are a lot of things that your Unix system -- right out of the box -- can tell you about files and processes.

    1 year 23 weeks ago

  • The quickest way to determine what and how many processors are installed on a Linux system is to turn to the mighty gateway of kernel data -- the /proc pseudo-filesystem. In it, you'll find a file called /proc/cpuinfo that provides a lot of information in the processors in your system. Read on to see how easily you can get answers to questions and an explanation of what those answers really tell you.

    1 year 24 weeks ago

  • Hard links are not called "hard" because they're difficult. They're just ... mildly elusive. Read on and find out why one long-time Unix admin thinks hard links are the penguin's meow.

    1 year 25 weeks ago

  • Planning to spend the next six months fighting with troublesome data that you might have to scrub, decode, reformat, store, classify, annotate, visualize, analyze, explain, report and then start all over again? Maybe you should first get some advice from others who have been there, done that.

    1 year 26 weeks ago

  • If you're only comfortable with CIDR when the / is followed by a multiple of 8, a quick refresher on how the numbers work might be just what you need for a balmy January afternoon.

    1 year 27 weeks ago

  • Before the chilly winds of a RIF blow in your direction or a pile of your friends take off for greener pastures, you need to be prepared with an easy way to freeze account and preserve what might be of value in the abandoned home directories. In today's post, we'll look at some commands for inactivating accounts on Unix systems and provide some starter scripts for you to adapt to your environment.

    1 year 28 weeks ago

  • If you love Unix but fear programming or have a kid who you'd like to convince that programming is fun, here's a book you really should consider.

    1 year 29 weeks ago

  • Complexity isn't all bad. Sometimes it comes with a tremendous boon to security. Are you ready to cozy up to SELinux? Maybe it's time.

    1 year 30 weeks ago

  • Hardening tips for Unix systems have been issued for decades, but when's the last time you stopped to review how your servers stack up against the latest advice from the sages? Let's check out some of the recommendations provided for Red Hat Enterprise Linux 5 and see what you might gain or lose by implementing them.

    1 year 31 weeks ago

  • As we find ourselves hurtling toward 2013, it's a good time to think about all the things that we Unix admins would never do ... and how that keeps us out of trouble.

    1 year 32 weeks ago

  • Do you get calls at odd hours because some critical service that you support on your Linux server has stopped working? Here's some late night reading that might help you get the rest you deserve.

    1 year 33 weeks ago

  • Iptables, more properly referred to as "iptables/netfilter" because of the two modules that are involved -- the userspace module "iptables" and the kernel module "netfilter" -- is the firewall that you'll find running by default on most Linux systems today.

    1 year 34 weeks ago

  • Setting limits on your Linux systems can both protect against certain types of failure and ensure that critical processes keep running when systems are heavily used. Take a look at the ulimit command and see what kind of shackles are limiting you – or maybe setting you free.

    1 year 35 weeks ago

  • The most typical use of Samba is to make Unix home directories or shared files available on Windows. Being most comfortable on the command line, I generally do this by opening a Command Prompt and entering NET USE commands.

    1 year 36 weeks ago

  • With the clocks turned back and the Big Vote about to happen, I'm up for a bit of nostalgia. And nothing pleases me more than doting on some of my favorite Unix commands, aliases and "tricks".

    1 year 37 weeks ago

  • I call this blog "Unix as a Second Language" for a reason. I spoke English long before I became a Unix geek and a well crafted sentence can still bring a thrill to my geeky little heart. The problem is that I find myself increasingly surrounded by people who just don't get some of the basic principles of the language.

    1 year 38 weeks ago

  • LVM (currently released as LVM2), the "logical volume manager", is a flexible storage manager for the Linux kernel. It allows you to add, remove and resize partitions to suit your needs.

    1 year 39 weeks ago

  • Just about anyone who works on the command line of a Unix/Linux systems knows about history. Having the ability to repeat their most recent command by just typing !! or the most recent command that starts with a particular letter by typing something like !s saves them a lot of typing and a lot of typos.

    1 year 40 weeks ago

  • If you've been thinking that you could really use an Intranet site for your small business, but you're worried about the costs associated with building and maintaining one yourself, you might want to take a look at Bitrix24.

    1 year 41 weeks ago

  • In the olden days of Unix, each file had an owner, a group, and a notion of "everybody else". These entities could be granted read, write and/or execute permission -- and that was as far as it went.

    1 year 42 weeks ago

  • More than a few Linux distributions have pulled up their stakes in the decades old System V method of booting and quietly moved to a better way of booting. Better, faster, easier to maintain, and less prone to problems.

    1 year 43 weeks ago

  • Anyone too comfortable with the idea of run states on Unix systems might not be ready to hear this, but the process of going from a cold piece of hardware to multi-user mode has taken a couple very sharp turns in the last six years or so.

    1 year 44 weeks ago

  • Linux has gone a long way to popularize the use of sudo.

    1 year 45 weeks ago

  • Q: Why don´t you see penguins in Britain? A: Because they´re afraid of Wales But, if you did, they'd probably be reading this fun new book -- Ubuntu Made Easy: A Project-Based Introduction to Linux, no starch press, 2012 is the most easy-to-read, properly pitched and fun Linux book that I've ever read.

    1 year 46 weeks ago

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