R: Terminate an R Session

quit {base} | R Documentation

## Terminate an R Session

### Description

The function `quit` or its alias `q` terminate the current R session.

### Usage

    quit(save = "default", status = 0, runLast = TRUE)
       q(save = "default", status = 0, runLast = TRUE)

### Arguments

`save` | a character string indicating whether the environment (workspace) should be saved, one of `"no"`, `"yes"`, `"ask"` or `"default"`.
`status` | the (numerical) error status to be returned to the operating system, where relevant. Conventionally `0` indicates successful completion.
`runLast` | should `.Last()` be executed?

### Details

`save` must be one of `"no"`, `"yes"`, `"ask"` or `"default"`. In the first case the workspace is not saved, in the second it is saved and in the third the user is prompted and can also decide not to quit. The default is to ask in interactive use but may be overridden by command-line arguments (which must be supplied in non-interactive use).

Immediately before normal termination, `.Last()` is executed if the function `.Last` exists and `runLast` is true. If in interactive use there are errors in the `.Last` function, control will be returned to the command prompt, so do test the function thoroughly. There is a system analogue, `.Last.sys()`, which is run after `.Last()` if `runLast` is true.

Exactly what happens at termination of an R session depends on the platform and GUI interface in use. A typical sequence is to run `.Last()` and `.Last.sys()` (unless `runLast` is false), to save the workspace if requested (and in most cases also to save the session history: see `savehistory`), then run any finalizers (see `reg.finalizer`) that have been set to be run on exit, close all open graphics devices, remove the session temporary directory and print any remaining warnings (e.g., from `.Last()` and device closure).

Some error status values are used by R itself. The default error handler for non-interactive use effectively calls `q("no", 1, FALSE)` and returns error status 1. Error status 2 is used for R ‘suicide’, that is a catastrophic failure, and other small numbers are used by specific ports for initialization failures. It is recommended that users choose statuses of 10 or more.

Valid values of `status` are system-dependent, but `0:255` are normally valid. (Many OSes will report the last byte of the value, that is report the value modulo 256. But not all.)

Windows calls the status the ‘error code’ or ‘exit code’. It is returned in the environment variable %ERRORLEVEL% in `cmd.exe`, and in LASTEXITCODE in Windows PowerShell. Note that the `Rterm` reliably reports the `status` value, but `Rgui` may give an error code from the GUI interface.

### Warning

The value of `.Last` is for the end user to control: as it can be replaced later in the session, it cannot safely be used programmatically, e.g. by a package. The other way to set code to be run at the end of the session is to use a finalizer: see `reg.finalizer`.

### Note

The `R.app` GUI on macOS has its own version of these functions with slightly different behaviour for the `save` argument (the GUI's ‘Startup’ preferences for this action are taken into account).

### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

### See Also

`.First` for setting things on startup.

### Examples

    ## Not run: ## Unix-flavour example
    .Last <- function() {
      graphics.off() # close devices before printing
      cat("Now sending PDF graphics to the printer:\n")
      system("lpr Rplots.pdf")
      cat("bye bye...\n")
    }
    quit("yes")
    ## End(Not run)

[Package base version 4.0.5 Index]