R: Kill a Process

pskill {tools} | R Documentation

## Kill a Process

### Description

`pskill` sends a signal to a process, usually to terminate it.

### Usage

    pskill(pid, signal = SIGTERM)

    SIGHUP
    SIGINT
    SIGQUIT
    SIGKILL
    SIGTERM
    SIGSTOP
    SIGTSTP
    SIGCHLD
    SIGUSR1
    SIGUSR2

### Arguments

`pid` | positive integers: one or more process IDs as returned by `Sys.getpid`.
`signal` | integer, most often one of the symbolic constants.

### Details

Signals are a C99 concept, but only a small number are required to be supported (of those listed, only `SIGINT` and `SIGTERM`). They are much more widely used on POSIX operating systems (which should define all of those listed here), which also support a `kill` system call to send a signal to a process, most often to terminate it. Function `pskill` provides a wrapper: it silently ignores invalid values of its arguments, including zero or negative pids.

In normal use on a Unix-alike, `Ctrl-C` sends `SIGINT`, `Ctrl-\` sends `SIGQUIT` and `Ctrl-Z` sends `SIGTSTP`: that and `SIGSTOP` suspend a process which can be resumed by `SIGCONT`.

The signals are small integers, but the actual numeric values are not standardized (and most do differ between OSes). The `SIG*` objects contain the appropriate integer values for the current platform (or `NA_INTEGER_` if the signal is not defined).

Only `SIGINT` and `SIGKILL` will be defined on Windows, and `pskill` will always use the Windows system call `TerminateProcess`.

### Value

A logical vector of the same length as `pid`, `TRUE` (for success) or `FALSE`, invisibly.

### See Also

Package parallel has several means to launch child processes which record the process IDs.

`psnice`

### Examples

    ## Not run:
    pskill(c(237, 245), SIGKILL)

    ## End(Not run)

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