Sandra Henry-Stocker
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Sandra Henry-Stocker
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How to squeeze the most out of Linux file compression
If you have any doubt about the many commands and options available on Linux systems for file compression, you might want to take a look at the output of the apropos compress command. Chances are you'll be surprised by the many commands that you can use for compressing and decompressing files, as well as for comparing compressed files, examining and searching through the content of compressed files, and even changing a compressed file from one format to another (i.e., .z format to .gz format).You're likely to see all of these entries just for the suite of bzip2 compression commands. Add in zip, gzip, and xz, and you've got a lot of interesting options.To read this article in full, please click here
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Linux for the Industry 4.0 era: New distro for factory automation
NXP Semiconductors, a world leader in secure connectivity solutions, just announced a Linux distribution that is intended to support factory automation. It's called Open Industrial Linux (OpenIL), and it's promising true industrial-grade security based on trusted computing, hardened software, cryptographic operations and end-to-end security.The fact that factory managers and industrial equipment manufacturers are turning to Linux is not surprising considering its operational stability, professional approach to system security, and its obvious low cost of ownership. The importance of the security and reliability of manufacturing security to the well being of any industrial nation is clear from the focus that DHS places on this sector.To read this article in full, please click here
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Why Linux can make you feel thankful or merely stuffed
Thanksgiving is tomorrow. While I’m looking forward to turkey, stuffing and pie, I’m also thankful to have been able to spend most of my career administering Unix and Linux systems. So, today’s post is going to focus on some of the things I’ve felt most thankful for and most gratified by over the span of more than 30 years with Unix and Linux.Also on Network World: 14 Linux apps that will change how you work There are many reasons why I came to appreciate Unix and then Linux and why they became such an important part of my life. These operating systems provided a focus and a career specialty that I've greatly enjoyed. I appreciate Linus Torvalds and the many thousands of developers who have contributed their time and energy into building a powerful, efficient and enjoyable operating system. I appreciate the many tools and commands that make them so easy to use and get my work done. And I appreciate the chances that I've had to share what I've learned with so many others. It's been fun, and it's been very rewarding.To read this article in full, please click here
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Building command groups with sudo
When managing your /etc/sudoers files, it’s a good idea to organize user privileges in ways that make them easier to manage over the long haul and to assign permissions based on the roles that users play in your organization. One very useful way is to group related commands together – such as all commands related to running backups or managing web sites – and assign them to the individuals or groups that require these privileges.Setting up command groups To create a command group, you would use what is called a Cmnd_Alias in your /etc/sudoers file and give the new command group a meaningful name. Here are some examples. Note that full pathnames should be specified for all of the commands included in a group. Otherwise, you are likely to see an error like this when you try to exit visudo. And remember to only edit /etc/sudoers with the visudo command to allow it to warn you in ways like this and prevent errors.To read this article in full, please click here
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How to build command groups with sudo
When managing your /etc/sudoers files, it’s a good idea to organize user privileges in ways that make them easier to manage over the long haul and to assign permissions based on the roles that users play in your organization.One very useful way to do that is to group related commands together — such as all commands related to running backups or managing web sites — and assign them to the individuals or groups that require these privileges.Setting up command groups in /etc/sudoers To create a command group, you use what is called a Cmnd_Alias in your /etc/sudoers file and give the new command group a meaningful name. Here are some examples. Note that full pathnames should be specified for all of the commands included in a group. Otherwise, you are likely to see an error like this when you try to exit visudo. And remember to only edit /etc/sudoers with the visudo command to allow it to warn you in ways like this and prevent errors.To read this article in full, please click here
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5 tricks for using the sudo command
The sudoers file can provide detailed control over user privileges, but with very little effort, you can still get a lot of benefit from sudo. In this post, we're going to look at some simple ways to get a lot of value out of the sudo command in Linux.Trick 1: Nearly effortless sudo usage The default file on most Linux distributions makes it very simple to give select users the ability to run commands as root. In fact, you don’t even have to edit the /etc/sudoers file in any way to get started. Instead, you just add the users to the sudo or admin group on the system and you’re done.Adding users to the sudo or admin group in the /etc/group file gives them permission to run commands using sudo.To read this article in full, please click here
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Future-proofing your career with IoT
What can you do to ensure your technical skills remain relevant and in demand even as technology evolves?For years, I've been suggesting that sysadmins and other technology professionals who want to stay ahead of the curve focus on: developing skills for the next wave of technology innovations routinely picking up some in-demand skills investing some of their time in side projects that may not pay off right away While this still seems to be excellent advice, it appears that a specific focus on IoT should be added to the list. Earlier this year, Gartner predicted that 20.4 billion IoT devices will be connecting in 2020. That's just over two years from now and that's a lot of devices. Srini Vemula, global product management leader at SenecaGlobal, believes that this influx of new IoT devices will lead to tens of thousands of new jobs in the IoT economy.To read this article in full or to leave a comment, please click here
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6 IoT skills that will future-proof your career
What can you do to ensure your technical skills remain relevant and in demand even as technology evolves?For years, I've suggested that sysadmins and other technology professionals who want to stay ahead of the curve focus on: Developing skills for the next wave of technology innovations Routinely picking up some in-demand skills Investing some of their time in side projects that may not pay off right away While that still seems to be excellent advice, it appears a specific focus on the Internet of Things (IoT) should be added to the list. Earlier this year, Gartner predicted that 20.4 billion IoT devices will be connecting in 2020. That's just over two years from now, and that's a lot of devices. Srini Vemula, global product management leader at SenecaGlobal, believes this influx of new IoT devices will lead to tens of thousands of new jobs in the IoT economy.To read this article in full or to leave a comment, please click here
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Beam me up and over – test driving telepresence technology
Telepresence has become a very intelligent business strategy, especially for companies that are spread across multiple sites or those with clients in many locations that they need to deal with on a fairly regular basis. Using what is in essence a fairly simple robot, anyone can transport himself to another location, move around through offices and interact face-to-face with people they might not otherwise ever meet. Granted they’re going to look something like large iPads held up by a couple metal rods riding on top of self-propelled vacuum cleaners, the experience is still surprisingly effective.I’ve recently had a chance to transport myself using one of the Beam presence systems built by Suitable Technologies. I sat in my office in the mountains in Virginia while being transported to an office suite in Palo Alto, California and interacted with two members of the staff. I had previously spoken with one of the same company’s customers at yet another location to get a feel for how they were using their Beams.To read this article in full or to leave a comment, please click here
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Beam me up and over – test driving telepresence technology
Telepresence has become a very intelligent business strategy, especially for companies that are spread across multiple sites or those with clients in many locations that they need to deal with on a fairly regular basis. Using what is in essence a fairly simple robot, anyone can transport himself to another location, move around through offices and interact face-to-face with people they might not otherwise ever meet. Granted they’re going to look something like large iPads held up by a couple metal rods riding on top of self-propelled vacuum cleaners, the experience is still surprisingly effective.I’ve recently had a chance to transport myself using one of the Beam presence systems built by Suitable Technologies. I sat in my office in the mountains in Virginia while being transported to an office suite in Palo Alto, California and interacted with two members of the staff. I had previously spoken with one of the same company’s customers at yet another location to get a feel for how they were using their Beams.To read this article in full or to leave a comment, please click here
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Beam me up and over – test driving telepresence technology
Telepresence has become a very intelligent business strategy, especially for companies that are spread across multiple sites or those with clients in many locations that they need to deal with on a fairly regular basis. Using what is in essence a fairly simple robot, anyone can transport himself to another location, move around through offices and interact face-to-face with people they might not otherwise ever meet. Granted they’re going to look something like large iPads held up by a couple metal rods riding on top of self-propelled vacuum cleaners, the experience is still surprisingly effective.I’ve recently had a chance to transport myself using one of the Beam presence systems built by Suitable Technologies. I sat in my office in the mountains in Virginia while being transported to an office suite in Palo Alto, California and interacted with two members of the staff. I had previously spoken with one of the same company’s customers at yet another location to get a feel for how they were using their Beams.To read this article in full or to leave a comment, please click here
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Beam me up and over — test-driving telepresence technology
Telepresence has become a very intelligent business strategy, especially for companies that are spread across multiple sites or for those that have clients in many locations that they need to deal with on a fairly regular basis. Using what is in essence a fairly simple robot, anyone can transport himself to another location, move around through offices and interact face to face with people they might not otherwise ever meet. Granted they’re going to look something like large iPads held up by a couple metal rods riding on top of self-propelled vacuum cleaners, but the experience is still surprisingly effective.I recently had a chance to transport myself using one of the Beam presence systems built by Suitable Technologies. I sat in my office in the mountains in Virginia while being transported to an office suite in Palo Alto, California, and interacted with two members of the staff. I had previously spoken with one of the same company’s customers at yet another location to get a feel for how they were using their Beams.To read this article in full or to leave a comment, please click here
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Beam me up and over — test-driving telepresence technology
Telepresence has become a very intelligent business strategy, especially for companies that are spread across multiple sites or for those that have clients in many locations that they need to deal with on a fairly regular basis. Using what is in essence a fairly simple robot, anyone can transport himself to another location, move around through offices and interact face to face with people they might not otherwise ever meet. Granted they’re going to look something like large iPads held up by a couple metal rods riding on top of self-propelled vacuum cleaners, but the experience is still surprisingly effective.I recently had a chance to transport myself using one of the Beam presence systems built by Suitable Technologies. I sat in my office in the mountains in Virginia while being transported to an office suite in Palo Alto, California, and interacted with two members of the staff. I had previously spoken with one of the same company’s customers at yet another location to get a feel for how they were using their Beams.To read this article in full or to leave a comment, please click here
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Scary Linux commands for Halloween
With Halloween so fast approaching, it’s time for a little focus on the spookier side of Linux. What commands might bring up images of ghosts, witches and zombies? Which might encourage the spirit of trick or treat?crypt Well, we’ve always got crypt. Despite its name, crypt is not an underground vault or a burial pit for trashed files, but a command that encrypts file content. These days “crypt” is generally implemented as a script that emulates the older crypt command by calling a binary called mcrypt to do its work. Using the mycrypt command directly is an even better option. $ mcrypt x Enter the passphrase (maximum of 512 characters) Please use a combination of upper and lower case letters and numbers. Enter passphrase: Enter passphrase: File x was encrypted. Note that the mcrypt command creates a second file with an added ".nc" extension. It doesn't overwrite the file you are encrypting.To read this article in full or to leave a comment, please click here
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More ways to examine network connections on Linux
The ifconfig and netstat commands are incredibly useful, but there are many other commands that can help you see what's up with you network on Linux systems. Today’s post explores some very handy commands for examining network connections.ip command The ip command shows a lot of the same kind of information that you'll get when you use ifconfig. Some of the information is in a different format – e.g., "192.168.0.6/24" instead of "inet addr:192.168.0.6 Bcast:192.168.0.255" and ifconfig is better for packet counts, but the ip command has many useful options.First, here's the ip a command listing information on all network interfaces.To read this article in full or to leave a comment, please click here
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More ways to examine network connections on Linux
The ifconfig and netstat commands are incredibly useful, but there are many other commands that can help you see what's up with you network on Linux systems. Today’s post explores some very handy commands for examining network connections.ip command The ip command shows a lot of the same kind of information that you'll get when you use ifconfig. Some of the information is in a different format – e.g., "192.168.0.6/24" instead of "inet addr:192.168.0.6 Bcast:192.168.0.255" and ifconfig is better for packet counts, but the ip command has many useful options.First, here's the ip a command listing information on all network interfaces.To read this article in full or to leave a comment, please click here
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Using the Linux find command with caution
A friend recently reminded me of a useful option that can add a little caution to the commands that I run with the Linux find command. It’s called -ok and it works like the -exec option except for one important difference — it makes the find command ask for permission before taking the specified action.Here’s an example. If you were looking for files that you intended to remove from the system using find, you might run a command like this:$ find . -name runme -exec rm {} \; Anywhere within the current directory and its subdirectories, any files named “runme” would be summarily removed — provided, of course, you have permission to remove them. Use the -ok command instead, and you’ll see something like this. The find command will ask for approval before removing the files. Answering y for “yes” would allow the find command to go ahead and remove the files one by one.To read this article in full or to leave a comment, please click here
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Examining network connections on Linux systems
There are a lot of commands available on Linux for looking at network settings and connections. In today's post, we're going to run through some very handy commands and see how they work.One very useful command is the ifquery command. This command should give you a quick list of network interfaces. However, you might only see something like this -- showing only the loopback interface: $ ifquery --list lo If this is the case, your /etc/network/interfaces file doesn't include information on network interfaces except for the loopback interface. You can add lines like the last two in the example below -- assuming DHCP is used to assign addresses -- if you'd like it to be more useful.To read this article in full or to leave a comment, please click here
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Getting Linux to ignore pings
The ping command sends one or more requests to a system asking for a response. It's typically used to check that a system is up and running, verify an IP address, or prove that the sending system can reach the remote one (i.e., verify the route).The ping command is also one that network intruders often use as a first step in identifying systems on a network that they might next want to attack. In this post, we're going to take a quick look at how ping works and then examine options for configuring systems to ignore these requests.How ping works The name "ping" came about because the ping command works in a way that is similar to sonar echo-location, which used sound propogation for navigation. The sound pulses were called "pings." The ping command on Unix and other systems sends an ICMP ECHO_REQUEST to a specified computer, which is then expected to send an ECHO_REPLY. The requests and replies are very small packets.To read this article in full or to leave a comment, please click here
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Managing users on Linux systems
Your Linux users may not be raging bulls, but keeping them happy is always a challenge as it involves managing their accounts, monitoring their access rights, tracking down the solutions to problems they run into, and keeping them informed about important changes on the systems they use. Here are some of the tasks and tools that make the job a little easier.Configuring accounts Adding and removing accounts is the easier part of managing users, but there are still a lot of options to consider. Whether you use a desktop tool or go with command line options, the process is largely automated. You can set up a new user with a command as simple as adduser jdoe and a number of things will happen. John’s account will be created using the next available UID and likely populated with a number of files that help to configure his account. When you run the adduser command with a single argument (the new username), it will prompt for some additional information and explain what it is doing.To read this article in full or to leave a comment, please click here