Running sendmail inside a docker image

Some cross-site-scripting attacks are possible when the attacker finds a weak spot in your source code and they can even leave the malicious code dormant for a long time before executing it. Also pulling more from a cultural level than a technical one are the concepts of crowdsourcing and crowdfunding …

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Create your own video streaming server with BioKnoppix

Time enough for a soapbox. The application can then trap into the kernel through this well-defined mechanism and execute only code that the kernel allows it to execute. In this case the semaphore clean up code simply discards the sem_undo data structure. Andrew Tannenbaum developed it for teaching purposes and …

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Sysadmin and Devops using vdir

If a developer needs a VM or if IT Ops needs to provision a server, they expect to do so quickly and painlessly; Linux's scalability allows for this rapid provisioning, as does its lack of cost-prohibitive licensing. These processes are said to be in the foreground. The file position starts …

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Principles of prelink under Linux

The module data structure is marked as DELETED and it is unlinked from the list of kernel modules. They work because they want to help themselves, their user base, or their software project. To make sure that even in a dual boot scenario office staff do not cling to their …

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Sysadmin and Devops using script

This is also true for a number of major system tasks where the hardware and software must cooperate closely to achieve their aims. Moreover, most programming languages (if they aren't limited to a particular OS) work on Linux. New processes are created via the fork() system call. Each approach has …

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The secret of lprintd

This subshell reinitializes itself, so that the effect is as if a new shell had been invoked to handle the script, with the exception that the locations of commands remembered by the parent are retained by the child. Linux can do everything NT does, usually faster, definately more stable and …

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Graphical tools for manipulating PDFs on the CRUX desktop

Keep in mind that these are only conventions---not rules. In fact, the current cloud functions-as-a-service (FaaS)/serverless computing model owes much of its heritage to the Unix philosophy. This chapter describes how Linux supports the network protocols known collectively as TCP/IP. Remember that the shell is a program providing …

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A lazy person's guide to mcopy

Each command comes with a manual page which can be used to learn about its function as well as what options and arguments each specific command accepts. Before I became involved in Free Software, I had far different opinions, ideas, and beliefs than I do today. A security breach unnoticed …

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How to evaluate error messages with showkey

Yet the human factor is probably one of the most significant in not only how smoothly the actual Linux conversion goes but also how well it is adopted and beneficial to your organization. 3D printing would've surely emerged even without Linux, but thanks to the widespread power of the platform …

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My emacs and metasend workflow

Typing the suspend character (typically ^Z, Control-Z) while a process is running causes that process to be stopped and returns you to bash. One more thing, if you don't want your programming Linux distro to be devoid of systemd, there's an OpenRC spin for that. We heartily recommend you get …

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Learn mesg to further your career

You can also edit boot options on the fly from the GRUB menu. The operating system then uses the computer hardware to perform the tasks required by the applications. These are independently developed pieces of software that work with the kernel in order to function as a complete operating system …

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Boost your mastery of hostid with these tips

This translates into a lot of time for UNIX to get it right - something Microsoft is still struggling with. So, /dev/hda2, the second partition of the primary IDE disk has a major number of 3 and a minor number of 2. If you tried to code up something similar …

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Succeed with op on Linux

If a parent process terminates before its child, the kernel will reparent the child to the init process. The takeover of software by corporations continued at a rapid pace, and free software was becoming an endangered species. Although the source code must be made freely available in all cases, there …

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The ultimate guide to rusersd

Linux does not. In this book, when I talk of gcc, I typically mean the program gcc, unless context suggests otherwise. When a user logs in, the login program checks the username and password, and then starts another program called the shell. As such it is possible to have two …

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Compiling your own kernel on Trustix

The command cd may be run without a location as we saw in the shortcut above but usually will be run with a single command line argument which is the location we would like to change into. Thus they are also called built-in commands. Programmers write Linux source code in …

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Getting started with inetd on Arch Linux

Without Linux, IoT would likely simply be too financially draining or require lock-in to a single vendor's stack. Fortunately for us there is an easy to use resource that can inform us about all the great things we can do on the command line. Some such devices are partionable, which …

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Getting a mail server up and running on Aurora SPARC Linux

In this article we will introduce you to why these accounts are important. In addition, by studying Linux, one is actually simultaneously becoming proficient with all Unix-like operating systems, including the proprietary flavors (i.e., versions) of UNIX such as Solaris and AIX, and Mac OS X (whose underlying operating …

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Are you making these mistakes with isovfy

At kernel initialization time, the address families built into the kernel register themselves with the BSD socket interface. That's right, all these guys all around the world worked very hard to make a neat, secure, efficient, good-looking system, and they are giving their work away for everybody to use freely …

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Quick and easy fixes using if

From the process's perspective, the view of the system is as though it alone were in control. Most systems built now use PCI and ISA buses to connect together the main system components. That's particularly important in a period of significant technological change. Thanks to Linux and the broader world …

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Get rid of etags once and for all

Its purpose is to provide a financial incentive for producing such works in order to benefit society as a whole. To understand what OSS is, you must first understand how source code is used to create programs. This subshell reinitializes itself, so that the effect is as if a new …

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At the Linux terminal with bash

For the purposes of the shell, a command which exits with a zero exit status has succeeded. The amount of malicious soft- ware for Linux systems remains incredibly low in comparison to other systems, and nearly all malicious Linux software available today is designed to breach unprotected Linux-based Android smartphones …

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Where to get more detail on git

In many ways, Linux and UNIX administration is today much easier than administration for popular commercial personal operating systems because it is much more transparent. But the Linux community is much more than the kernel, and needs contributions from lots of other people besides programmers. Loadlin works from a DOS …

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Developing with Ruby on Rails in a Linux container

What we call the Linux operating system today is really the combination of two efforts from the early 1990s. I should like to point out you should NEVER be logged in as root all the time, as you may damage your system. Setting up TCP/IP connections is very different …

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Shortcuts for ip made easy

Hedging our bets is what this issue of Troubleshooting Professional Magazine is all about. In this case the semaphore clean up code simply discards the sem_undo data structure. Commands run as a result of command substitu- tion ignore the keyboard-generated job control signals SIGTTIN, SIGTTOU, and SIGTSTP. All system times …

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Tips and tricks for using CUPS for printing with Knoppix

We who are enthusiastic about GNU/Linux want to spread that freedom around. However, this is no less "programming" than anything else. Recently, Linux has replaced this security system with a more general capabilities system. Because it is free software, licensed under the GNU General Public License, Linux obviates the …

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Quick and easy fixes using mount

It is less expensive to acquire. Many OSes don't provide uptime information and thus can't be included; this includes AIX, AS/400, Compaq Tru64, DG/UX, MacOS, NetWare, NT3/Windows 95, NT4/Windows 98, OS/2, OS/390, SCO UNIX, Sony NEWS-OS, SunOS 4, and VM. It'll need a lot …

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Learn apropos to further your career

Originally, virtually all software was freely available to copy, use, study, modify, improve and give away. But, as we all know, there are typically many directories on a system. Until Linux came along it was either Windows or Macintosh - take it or leave it. The IP protocol layer itself uses …

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Data collection under Ubuntu

bash allows the current readline key bindings to be displayed or modified with the bind built-in command. Libraries were written and ported, filesystems developed, and hardware drivers written for many popular devices. Other common sections in ELF executables are the absolute section (which contains nonrelocatable symbols) and the undefined section …

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How to manage storage on Linux with LVM

The stuff which really needs to be automated is automated and the stuff which can teach you something is left manual. Not often are our basic rights thought of in the context of technology, but as more and more our lives are dependent on technology, it is a rapidly growing …

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No more mistakes with pushd

When I have unmounted the VFAT partition the system detects that I no longer need the VFAT file system module and removes it from the system. If you can use a computer or other electronic device, you can use Linux. The fact that open source code offers complete transparency acts …

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Work in progress asynchronous email client

Sometimes the DMA channel for a device can be set by jumpers; a number of ethernet devices use this technique. The control bus contains various lines used to route timing and control signals throughout the system. If one process crashes it will not cause another process in the system to …

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Open the gates for gpgsplit

Moreover, most programming languages (if they aren't limited to a particular OS) work on Linux. Because your server will be probably Linux-based as well, it will be easier for you to mimic behaviors, use similar software and packages and automate work flows for your deployment processes. You can easily see …

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Emotional support animal

The term “emotional support animal” is in the news at present, mainly, sadly, because of its predictable abuse. In Japan, companion animals are petto or aigando butsu, animals to love, or play with, or take pleasure in, which just about covers it all. The next time you greet your own …

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The Mazambican poachers

To kill rhinos, Mozambican poachers appear to prefer hunting rifles over other firearms available to them. There is evidence that Czech CZ 550 bolt-action rifles have become more popular with poachers in recent years. While obtaining a rifle through official channels in Mozambique can take up to six months, there …

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Columbias corporate security

While Colombia is a special case in some ways because of its long history of conflict, extractive industry activities in less extreme settings are increasingly marked by the presence of private, corporate security. The result is a variety of collaborative partnerships between public and private, formal and informal types of …

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Open the gates for fgrep

Its entries are also device_struct data structures. Over the years, Unix systems have supported a handful of different special files. This must happen as the module cannot expect to be loaded at the same address twice let alone into the same address in two different Linux systems. Most open source …

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Linux adventures with tar

As a result, most desktop and server Linux systems that run antivirus and anti-malware software today do so because they host files that may be shared with Win- dows computers. The command cd may be run without a location as we saw in the shortcut above but usually will be …

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Open the gates for strip

The API merely defines the interface; the piece of software that actually provides the API is known as the implementation of the API. Most recently, the U.S. Before I became involved in Free Software, I had far different opinions, ideas, and beliefs than I do today. This highly stable …

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