system {base} | R Documentation |
system
invokes the OS command specified by command
.
system(command, intern = FALSE, ignore.stderr = FALSE)
command |
the system command to be invoked, as a string. |
intern |
a logical (not NA ) which indicates whether to
make the output of the command an R object. Not available unless
popen is supported on the platform. |
ignore.stderr |
a logical indicating whether error messages (written to ‘stderr’) should be ignored. |
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
. Output lines of more than 8095 characters will be split.
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.
Error messages written to ‘stderr’ will be sent by the shell to
the terminal unless ignore.stderr = TRUE
. They can be captured
(in the most likely shells) by
system("some command 2>&1", intern=TRUE)
unix
is a deprecated alternative, available for
backwards compatibility.
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 this will be reported on the shell's
‘stderr’ (unless popen
is not supported, when there is an R
error). (Output lines of more than 8095 characters will be split.)
If intern = FALSE
, the return value is a system error code
(0
for success).
.Platform
for platform specific variables.
# list all files in the current directory using the -F flag ## Not run: system("ls -F") # t1 is a character vector, each one # representing a separate line of output from who # (if the platform has popen and who) t1 <- try(system("who", TRUE)) try(system("ls fizzlipuzzli", TRUE, TRUE)) # empty since file doesn't exist