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Disown (Unix)
In the Unix shells ksh, bash, fish and zsh, the disown builtin command is used to remove jobs from the job table, or to mark jobs so that a SIGHUP signal is not sent to them if the parent shell receives it (e.g. if the user logs out). See also * nohup, a 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 comm ... command to ignore the HUP (hangup) signal External links Bash Reference Manual: Job Control Builtins {{Unix commands System administration ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix Shell
A Unix shell is a Command-line_interface#Command-line_interpreter, command-line interpreter or shell (computing), shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting language, and is used by the operating system to control the execution of the system using shell scripts. Users typically interact with a Unix shell using a terminal emulator; however, direct operation via serial hardware connections or Secure Shell are common for server systems. All Unix shells provide filename Wildcard character, wildcarding, Pipeline (Unix), piping, here documents, command substitution, Variable (programming), variables and control flow, control structures for Conditional (programming), condition-testing and iteration. Concept Generally, a ''shell'' is a program that executes other programs in response to text commands. A sophisticated shell can also change the environment in which other programs exe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KornShell
KornShell (ksh) is a Unix shell which was developed by David Korn (computer scientist), David Korn at Bell Labs in the early 1980s and announced at USENIX Annual Technical Conference, USENIX on July 14, 1983. The initial development was based on Bourne shell source code. Other early contributors were Bell Labs developers Mike Veach and Pat Sullivan, who wrote the Emacs and Vi (text editor), vi-style line editing modes' code, respectively. KornShell is backward-compatible with the Bourne shell and includes many features of the C shell, inspired by the requests of Bell Labs users. Features KornShell complies with POSIX#POSIX.2, POSIX.2, Shell and Utilities, Command Interpreter (IEEE Std 1003.2-1992.) Major differences between KornShell and the traditional Bourne shell include: * Job control (Unix), job control, alias (command), command aliasing, and command history designed after the corresponding C shell features; job control was added to the Bourne Shell in 1989 * a choice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bash (Unix Shell)
In computing, Bash (short for "''Bourne Again SHell''") is an interactive command interpreter and command programming language developed for UNIX-like operating systems. Created in 1989 by Brian Fox for the GNU Project, it is supported by the Free Software Foundation and designed as a 100% free alternative for the Bourne shell (sh) and other proprietary Unix shells. Since its inception, Bash has gained widespread adoption and is commonly used as the default login shell for numerous Linux distributions. It holds historical significance as one of the earliest programs ported to Linux by Linus Torvalds, alongside the GNU Compiler ( GCC). It is available on nearly all modern operating systems, making it a versatile tool in various computing environments. As a command-line interface (CLI), Bash operates within a terminal emulator, or text window, where users input commands to execute various tasks. It also supports the execution of commands from files, known as shell scripts, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friendly Interactive Shell
Fish (friendly interactive shell; stylized in lowercase) is a Unix-like shell with a focus on interactivity and usability. Fish is designed to be feature-rich by default, rather than highly configurable, and does not adhere to POSIX shell standards by design. Features Fish displays incremental suggestions as the user types, based on command history and the current directory. This functions similarly to Bash's history search, but is always on, giving the user continuous feedback while typing commands. Fish also includes feature-rich tab completion, with support for expanding file paths (with wildcards and brace expansion), environment variables, and command-specific completions. Command-specific completions, including options with descriptions, can be to some extent generated from the commands' man pages, but custom completions can also be included with software or written by users of the shell. The creator of Fish preferred to add new features as commands rather than syntax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shell Builtin
In computing, a shell builtin is a Command (computing), command or a Subroutine, function, exposed by a Shell (computing), shell, that is implemented in the shell itself, instead of an external computer program, program which the shell would load and execute. A shell builtin starts faster than an external program because there is no program loading overhead. However, its implementation code is in the shell program, and thus modifying it requires modifying the shell. Therefore, a shell builtin is usually only used for simple, almost trivial, commands, such as text output. Some commands must be implemented as builtins due to the nature of the operating system. Notably, the cd (command), cd command, which changes the working directory of the shell is often a builtin since a program runs in a separate Process (computing), process and working directory is specific to each process. Running cd as an external program would not affect the working directory of the shell that loaded it. See ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Job Control (Unix)
In Unix and Unix-like operating systems, job control refers to control of jobs by a shell, especially interactively, where a "job" is a shell's representation for a process group. Basic job control features are the suspending, resuming, or terminating of all processes in the job/process group; more advanced features can be performed by sending signals to the job. Job control is of particular interest in Unix due to its multiprocessing, and should be distinguished from job control generally, which is frequently applied to sequential execution (batch processing). Overview When using Unix or Unix-like operating systems via a terminal (or terminal emulator), a user will initially only have a single process running, their interactive shell (it may or may not be a login shell). Most tasks (directory listing, editing files, etc.) can easily be accomplished by letting the program take control of the terminal and returning control to the shell when the program exits – formally, by atta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIGHUP
On POSIX-compliant platforms, SIGHUP ("signal hang up") is a signal sent to a process when its controlling terminal is closed. It was originally designed to notify the process of a serial line drop. SIGHUP is a symbolic constant defined in the header file signal.h. History Access to computer systems for many years consisted of connecting a terminal to a mainframe system via a serial line and the RS-232 protocol. When a system of software interrupts, called signals, was being developed, one of those signals was designated for use on hangup. SIGHUP would be sent to programs when the serial line was dropped, often because the connected user terminated the connection by hanging up the modem. The system would detect the line was dropped via the lost Data Carrier Detect (DCD) signal. Signals have always been a convenient method of inter-process communication (IPC), but in early implementations there were no user-definable signals (such as the later additions of SIGUSR1 and SIGU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logout
In computer security, logging in (or logging on, signing in, or signing on) is the process by which an individual gains access to a computer system or program by identifying and authenticating themselves. Typically, user credentials consist of a username and a password. These credentials themselves are sometimes referred to as ''a'' login. Modern secure systems often require a second factor, such as email or SMS confirmation for extra security. Social login allows a user to use an existing cell phone number, or user credentials from another email or social networking service to sign in or create an account on a new website. When access is no longer needed, the user can log out, log off, sign out or sign off. Procedure Logging in is usually used to enter a specific page, website, platform or application, which trespassers cannot see. Once the user is logged in, the login token may be used to track what actions the user has taken while connected to the site. Loggin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nohup
nohup is a POSIX command which means "no hang up". Its purpose is to execute a command such that it ignores the HUP (hangup) signal and therefore does not stop when the user logs out. Output that would normally go to the terminal goes to a file called , if it has not already been redirected. Use The first of the commands below starts the program abcd in the background in such a way that the subsequent logout does not stop it. $ nohup abcd & $ exit Note that these methods prevent the process from being sent a 'stop' signal on logout, but if input/output is being received for these standard I/O files (stdin, stdout, or stderr), they will still hang the terminal. See Overcoming hanging, below. nohup is often used in combination with the nice command to run processes on a lower priority. $ nohup nice abcd & Implementations Some shells (e.g. bash) provide a shell builtin that may be used to prevent SIGHUP being sent or propagated to existing jobs, even if they were not sta ... [...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] |
