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Rex (software)
(R)?ex or simply Rex is an open source remote execution, configuration management and software deployment tool. It combines Perl and Secure Shell (SSH) for a portable, centralistic approach to its problem domain. ''Rex'' is an acronym for "Remote Execution". History Rex originated from the need of a flexible, parallel remote execution application with software deployment and configuration management capabilities. Unsatisfied with available implementations in 2010, the author of Rex, Jan Gehring, decided to implement a Perl-based tool to cope with his requirements. Design Rex is a stand-alone application executing either a single command or so-called ''tasks''. Tasks are specified on the command line and are defined in ''Rexfiles''. A Rexfile takes a similar role for remote execution as a Makefile does for application installation. It is defined via a small DSL, but is essentially a Perl script. Therefore, it can contain arbitrary Perl as well. For code reuse, configurat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perl (programming Language)
Perl is a high-level, general-purpose, interpreted, dynamic programming language. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language". Perl was developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions. Perl originally was not capitalized and the name was changed to being capitalized by the time Perl 4 was released. The latest release is Perl 5, first released in 1994. From 2000 to October 2019 a sixth version of Perl was in development; the sixth version's name was changed to Raku. Both languages continue to be developed independently by different development teams which liberally borrow ideas from each other. Perl borrows features from other programming languages including C, sh, AWK, and sed. It provides text processing facilities without the arbitrary data-length limits of man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domain-specific Language
A domain-specific language (DSL) is a computer language specialized to a particular application domain. This is in contrast to a general-purpose language (GPL), which is broadly applicable across domains. There are a wide variety of DSLs, ranging from widely used languages for common domains, such as HTML for web pages, down to languages used by only one or a few pieces of software, such as MUSH soft code. DSLs can be further subdivided by the kind of language, and include domain-specific ''markup'' languages, domain-specific ''modeling'' languages (more generally, specification languages), and domain-specific ''programming'' languages. Special-purpose computer languages have always existed in the computer age, but the term "domain-specific language" has become more popular due to the rise of domain-specific modeling. Simpler DSLs, particularly ones used by a single application, are sometimes informally called mini-languages. The line between general-purpose languages and doma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of Open-source Configuration Management Software
This is a comparison of notable free and open-source configuration management software, suitable for tasks like server configuration, orchestration and infrastructure as code typically performed by a system administrator. Basic properties "Verify mode" (also called dry run) refers to having an ability to determine whether a node is conformant with a guarantee of not modifying it, and typically involves the exclusive use of an internal language supporting read-only mode for all potentially system-modifying operations. ''Mutual authentication'' (mutual auth) refers to the client verifying the server and vice versa. ''Agent'' describes whether additional software daemons are required. Depending on the management software these agents are usually deployed on the target system or on one or many central ''controller'' servers. Although Agent-less = No is colored red and might seem to be a negative, instead, having an agent can be considered quite advantageous to many. Consider ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Machine
In computing, a virtual machine (VM) is the virtualization or emulator, emulation of a computer system. Virtual machines are based on computer architectures and provide the functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination of the two. Virtual machines differ and are organized by their function, shown here: * ''System virtual machines'' (also called full virtualization VMs, or SysVMs) provide a substitute for a real machine. They provide the functionality needed to execute entire operating systems. A hypervisor uses native code, native execution to share and manage hardware, allowing for multiple environments that are isolated from one another yet exist on the same physical machine. Modern hypervisors use hardware-assisted virtualization, with virtualization-specific hardware features on the host CPUs providing assistance to hypervisors. * ''Process virtual machines'' are designed to execute computer programs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernel Module
A loadable kernel module (LKM) is an executable library that extends the capabilities of a running kernel, or so-called ''base kernel'', of an operating system. LKMs are typically used to add support for new hardware (as device drivers) and/or filesystems, or for adding system calls. When the functionality provided by an LKM is no longer required, it can be unloaded in order to free memory and other resources. Most current Unix-like systems and Windows support loadable kernel modules but with different names, such as kernel loadable module (kld) in FreeBSD, kernel extension (kext) in macOS (although support for third-party modules is being dropped), kernel extension module in AIX, dynamically loadable kernel module in HP-UX, kernel-mode driver in Windows NT and downloadable kernel module (DKM) in VxWorks. They are also known as kernel loadable module (KLM), or simply as kernel module (KMOD). Advantages Without loadable kernel modules, an operating system would have to inclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cron
The cron command-line utility is a job scheduler on Unix-like operating systems. Users who set up and maintain software environments use cron to schedule jobs (commands or shell scripts), also known as cron jobs, to run periodically at fixed times, dates, or intervals. It typically automates system maintenance or administration—though its general-purpose nature makes it useful for things like downloading files from the Internet and downloading email at regular intervals. Cron is most suitable for scheduling repetitive tasks. Scheduling one-time tasks can be accomplished using the associated ''at'' utility. Cron's name originates from Chronos, the Greek word for time. Overview The actions of cron are driven by a crontab (cron table) file, a configuration file that specifies shell commands to run periodically on a given schedule. The crontab files are stored where the lists of jobs and other instructions to the cron daemon are kept. Users can have their own individual cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rex Configuration Management, Example Run
Rex or REX may refer to: * Rex (title) (Latin: king, ruler, monarch), a royal title ** King of Rome (Latin: Rex Romae), chief magistrate of the Roman Kingdom Animals Dogs * Rex (Ronald Reagan's dog) * Rex (search and rescue dog), a dog that received a 1945 Dickin Medal for bravery Other animals * ''-rex'', a taxonomic suffix used to describe certain large animals * Tyrannosaurus rex, a large predatory cretaceous dinosaur * Rex (horse) or Rex the Wonder Horse, star of 15 Hollywood motion pictures * Rex rabbit, a breed of rabbit ** Rex mutation, a type of mutation affecting the fur of the rex rabbit ** One of at least three types of rabbit fur collectively known as "rex fur" * A category of domestic cat breeds, such as the Devon Rex Computing and technology * REX prefix, used by the x86-64 instruction encoding * Rexx (originally named Rex), a computer programming language * REX, an audio file format; see REX2 * .rex (other), file extension used by Rexx scripts and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux
Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, packaged as a Linux distribution (distro), which includes the kernel and supporting system software and library (computing), libraries—most of which are provided by third parties—to create a complete operating system, designed as a clone of Unix and released under the copyleft GPL license. List of Linux distributions, Thousands of Linux distributions exist, many based directly or indirectly on other distributions; popular Linux distributions include Debian, Fedora Linux, Linux Mint, Arch Linux, and Ubuntu, while commercial distributions include Red Hat Enterprise Linux, SUSE Linux Enterprise, and ChromeOS. Linux distributions are frequently used in server platforms. Many Linux distributions use the word "Linux" in their name, but the Free ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secure Shell
The Secure Shell Protocol (SSH Protocol) is a cryptographic network protocol for operating network services securely over an unsecured network. Its most notable applications are remote login and command-line execution. SSH was designed for Unix-like operating systems as a replacement for Telnet and unsecured remote Unix shell protocols, such as the Berkeley Remote Shell (rsh) and the related rlogin and rexec protocols, which all use insecure, plaintext methods of authentication, like passwords. Since mechanisms like Telnet and Remote Shell are designed to access and operate remote computers, sending the authentication tokens (e.g. username and password) for this access to these computers across a public network in an unsecured way poses a great risk of 3rd parties obtaining the password and achieving the same level of access to the remote system as the telnet user. Secure Shell mitigates this risk through the use of encryption mechanisms that are intended to hide th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
