system                 package:base                 R Documentation

Invoke a System Command

Description:

     `system' invokes the OS command specified by `command'.

Usage:

     system(command, intern = FALSE, ignore.stderr = FALSE)

Arguments:

 command: the system command to be invoked, as a string.

  intern: a logical, indicates whether to make the output of the
          command an R object.

ignore.stderr: a logical indicating whether error messages (written to
          `stderr') should be ignored.

Details:

     If `intern' is `TRUE' then `popen' is used to invoke the command
     and the output collected, line by line, into an R `character'
     vector which is returned as the value of `system'.

     If `intern' is `FALSE' then the C function `system' is used to
     invoke the command and the value returned by `system' is the exit
     status of this function.

     `unix' is a deprecated alternative, available for backwards
     compatibility.

Value:

     If `intern=TRUE', a character vector giving the output of the
     command, one line per character string. If the command could not
     be run or gives an error a R error is generated.

     If `intern=FALSE', the return value is an error code.

See Also:

     `.Platform' for platform specific variables.

Examples:

     # list all files in the current directory using the -F flag
     system("ls -F")

     # t1 is a character vector, each one
     # representing a separate line of output from who
     t1 <- system("who", TRUE)

     system("ls fizzlipuzzli", TRUE, TRUE)# empty since file doesn't exist

