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Ps (Unix)
In most Unix and Unix-like operating systems, the ps (''process status'') program displays the currently-running processes. The related Unix utility top provides a real-time view of the running processes. Implementations KolibriOS includes an implementation of the command. The command has also been ported to the IBM i operating system. In Windows PowerShell, ps is a predefined command alias for the Get-Process cmdlet, which essentially serves the same purpose. Examples # ps PID TTY TIME CMD 7431 pts/0 00:00:00 su 7434 pts/0 00:00:00 bash 18585 pts/0 00:00:00 ps Users can pipeline ps with other commands, such as less to view the process status output one page at a time: $ ps -A , less Users can also utilize the ps command in conjunction with the grep command (see the pgrep and pkill commands) to find information about a single process, such as its id: $ # Trying to find the PID of `firefox-bin` which is 2701 $ ps -A , grep firefox-b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AT&T Bell Laboratories
Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world. As a former subsidiary of the American Telephone and Telegraph Company (AT&T), Bell Labs and its researchers have been credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B (programming language), B, C (programming language), C, C++, S (programming language), S, SNOBOL, AWK, AMPL, and others, throughout the 20th century. Eleven Nobel Prizes and five Turing Awards have been awarded for work completed at Bell Laboratories. Bell Labs had its origin in the complex corporate organization of the Bell System telepho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows PowerShell
PowerShell is a shell program developed by Microsoft for task automation and configuration management. As is typical for a shell, it provides a command-line interpreter for interactive use and a script interpreter for automation via a language defined for it. Originally only for Windows, known as Windows PowerShell, it was made open-source and cross-platform on August 18, 2016, with the introduction of PowerShell Core. The former is built on the .NET Framework; the latter on .NET (previously .NET Core). PowerShell is bundled with current versions of Windows and can be installed on macOS and Linux. Since Windows 10 build 14971, PowerShell replaced Command Prompt as the default command shell exposed by File Explorer. In PowerShell, administrative tasks are generally performed via ''cmdlets'' (pronounced ''command-lets''), which are specialized .NET classes implementing a particular operation. These work by accessing data in different data stores, like the file system or W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. Most early computers only had a front panel to input or display bits and had to be connected to a terminal to print or input text through a keyboard. Teleprinters were used as early-day hard-copy terminals and predated the use of a computer screen by decades. The computer would typically transmit a line of data which would be printed on paper, and accept a line of data from a keyboard over a serial or other interface. Starting in the mid-1970s with microcomputers such as the Sphere 1, Sol-20, and Apple I, display circuitry and keyboards began to be integrated into personal and workstation computer systems, with the computer handling character generation and outputting to a CRT display such as a computer monitor or, sometimes, a consumer TV, but most larger computers continued to require terminal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environment Variable
An environment variable is a user-definable value that can affect the way running processes will behave on a computer. Environment variables are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store temporary files, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process. They were introduced in their modern form in 1979 with Version 7 Unix, so are included in all Unix operating system flavors and variants from that point onward including Linux and macOS. From PC DOS 2.0 in 1982, all succeeding Microsoft operating systems, including Microsoft Windows, and OS/2 also have included them as a feature, although with somewhat different syntax, usage and standard variable names. Design In all Unix and Unix-like systems, as well as on Windows, each process has its own separate set of environment vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
POSIX
The Portable Operating System Interface (POSIX; ) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines application programming interfaces (APIs), along with command line shells and utility interfaces, for software compatibility (portability) with variants of Unix and other operating systems. POSIX is also a trademark of the IEEE. POSIX is intended to be used by both application and system developers. As of POSIX 2024, the standard is aligned with the C17 language standard. Name Originally, the name "POSIX" referred to IEEE Std 1003.1-1988, released in 1988. The family of POSIX standards is formally designated as IEEE 1003 and the ISO/IEC standard number is ISO/ IEC 9945. The standards emerged from a project that began in 1984 building on work from related activity in the ''/usr/group'' association. Richard Stallman suggested the name ''POSIX'' to the IEEE instead of the former ''IEEE-IX''. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single UNIX Specification
The Single UNIX Specification (SUS) is a standard for computer operating systems, compliance with which is required to qualify for using the "UNIX" trademark. The standard specifies programming interfaces for the C language, a command-line shell, and user commands. The core specifications of the SUS known as ''Base Specifications'' are developed and maintained by the Austin Group, which is a joint working group of IEEE, ISO/IEC JTC 1/SC 22/WG 15 and The Open Group. If an operating system is submitted to The Open Group for certification and passes conformance tests, then it is deemed to be compliant with a UNIX standard such as UNIX 98 or UNIX 03. Very few BSD and Linux-based operating systems are submitted for compliance with the Single UNIX Specification, although system developers generally aim for compliance with POSIX standards, which form the core of the Single UNIX Specification. The latest SUS consists of two parts: the ''base specifications'' technically iden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for efficient use of the system and may also include accounting software for cost allocation of Scheduling (computing), processor time, mass storage, peripherals, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computerfrom cellular phones and video game consoles to web servers and supercomputers. , Android (operating system), Android is the most popular operating system with a 46% market share, followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resident Set Size
In computing, resident set size (RSS) is the portion of memory (measured in kilobytes) occupied by a process that is held in main memory Computer data storage or digital data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processin ... ( RAM). The rest of the occupied memory exists in the swap space or file system, either because some parts of the occupied memory were paged out, or because some parts of the executable were never loaded. See also * * * * * * References External links Simple resident set size limits LWN.net, August 10, 2004, by Jonathan Corbet ELC: How much memory are applications really using? LWN.net, April 18, 2007, by Jonathan Corbet Memory management {{Operating-system-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nice (Unix)
nice is a program found on Unix and Unix-like operating systems such as Linux. It directly maps to a kernel call of the same name. nice is used to invoke a utility or shell script with a particular CPU priority, thus giving the process more or less CPU time than other processes. A niceness of -20 is the lowest niceness, or highest priority. The default niceness for processes is inherited from its parent process and is usually 0. Systems have diverged on what priority is the lowest. Linux systems document a niceness of 19 as the lowest priority, BSD systems document 20 as the lowest priority. In both cases, the "lowest" priority is documented as running only when nothing else wants to. Etymology ''Niceness value'' is a number attached to processes in *nix systems, that is used along with other data (such as the amount of I/O done by each process) by the kernel process scheduler to calculate a process' 'true priority'which is used to decide how much CPU time is allocated t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pkill
(see ) is a command-line utility initially written for use with the Solaris 7 operating system in 1998. It has since been reimplemented for Linux and some BSDs. As with the and commands, is used to send signals to processes. The command allows the use of extended regular expression A regular expression (shortened as regex or regexp), sometimes referred to as rational expression, is a sequence of characters that specifies a match pattern in text. Usually such patterns are used by string-searching algorithms for "find" ... patterns and other matching criteria. Example usage Kill the most recently created process: pkill -n acroread Send a USR1 signal to process: pkill -USR1 acroread See also Some other unix commands related to process management and killing include: * , which sends signals processes by process ID instead of by pattern-matching against the name. * , which changes the priority of a process. * and , which display a list of processes and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pgrep
pgrep is a command-line utility initially written for use with the Solaris 7 operating system by Mike Shapiro. It has since been available in illumos and reimplemented for the Linux and BSDs ( DragonFly BSD, FreeBSD, NetBSD, and OpenBSD). It searches for all the named processes that can be specified as extended regular expression patterns, and—by default—returns their process ID. Alternatives include pidof (finds process ID given a program name) and ps. Example usage The default behaviour of pgrep (returning the process identifier of the named tasks) simplifies an otherwise complex task and is invoked with: $ pgrep 'bash' Which is roughly equivalent to: $ ps ax , awk ' $5 ~ /bash/ ' Additional functionality of pgrep is listing the process name as well as the PID (-l Lists the process name as well as the process ID) of all processes belonging to the group alice (-G Only match processes whose real group ID is listed. Either the numerical or symbolical value ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grep
grep is a command-line utility for searching plaintext datasets for lines that match a regular expression. Its name comes from the ed command g/re/p (global regular expression search and print), which has the same effect. grep was originally developed for the Unix operating system, but later became available for all Unix-like systems and some others such as OS-9. History Before it was named, grep was a private utility written by Ken Thompson to search files for certain patterns. Doug McIlroy, unaware of its existence, asked Thompson to write such a program. Responding that he would think about such a utility overnight, Thompson actually corrected bugs and made improvements for about an hour on his own program called "s" (short for "search"). The next day he presented the program to McIlroy, who said it was exactly what he wanted. Thompson's account may explain the belief that grep was written overnight. Thompson wrote the first version in PDP-11 assembly language to help Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
