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In either case, the shell redirects I/O appropriately, and sends the SIGCONT signal to the process, which causes the operating system to resume its execution. In Bash, a program can be started as a background job by appending an ampersand (&) to the command line; its output is directed to the terminal (potentially interleaved with other ...
If the process receiving SIGHUP is a Unix shell, then as part of job control it will often intercept the signal and ensure that all stopped processes are continued before sending the signal to child processes (more precisely, process groups, represented internally by the shell as a "job"), which by default terminates them. [2]
In Unix and other POSIX-compatible systems, the parent process can retrieve the exit status of a child process using the wait() family of system calls defined in wait.h. [10] Of these, the waitid() [ 11 ] call retrieves the full exit status, but the older wait() and waitpid() [ 12 ] calls retrieve only the least significant 8 bits of the exit ...
LXSS Manager Service is the service in charge of interacting with the subsystem (through the drivers lxss.sys and lxcore.sys), and the way that Bash.exe (not to be confused with the Shells provided by the Linux distributions) launches the processes, as well as handling the Linux system calls and the binary locks during their execution. [38]
In particular, the POSIX specification and the Linux man page signal (7) require that all system functions directly or indirectly called from a signal function are async-signal safe. [ 6 ] [ 7 ] The signal-safety(7) man page gives a list of such async-signal safe system functions (practically the system calls ), otherwise it is an undefined ...
Shellshock, also known as Bashdoor, [1] is a family of security bugs [2] in the Unix Bash shell, the first of which was disclosed on 24 September 2014.Shellshock could enable an attacker to cause Bash to execute arbitrary commands and gain unauthorized access [3] to many Internet-facing services, such as web servers, that use Bash to process requests.
Background execution allows a shell to run a command without user interaction in the terminal, freeing the command line for additional work with the shell. POSIX shells and other Unix shells allow background execution by using the & character at the end of command. In PowerShell, the Start-Process [43] or Start-Job [44] cmdlets can be used.
The Bash command-line completion system is very flexible and customizable, and is often packaged with functions that complete arguments and filenames for specific programs and tasks. Bash's syntax has many extensions lacking in the Bourne shell. Bash can perform integer calculations ("arithmetic evaluation") without spawning external processes.