For example, this PowerShell command returns the top 5 largest files in the directory:
gci -r |sort Length -desc |select fullname -f 5
Is it possible to run it in R and assign it to a variable?
I tried this:
system("gci -r|sort Length -desc|select fullname -f 5")
Warning message:
running command 'gci -r|sort Length -desc|select fullname -f 5' had status 127
Shouldn't I use system() here?
You'll probably need to run it as (assuming PowerShell is in your path):
system("powershell -command \"gci -r|sort Length -desc|select fullname -f 5\"")
or, if you're not keen on escaping " with \".
system('powershell -command "gci -r|sort Length -desc|select fullname -f 5"')
I'm also assuming that's how R escapes and embeds quotes in strings (from my cursory googling about string handling in R).
If you wish to capture the output to a variable (specifically, a character vector) you need to use the intern = TRUE argument:
res <- system('powershell -command "gci -r|sort Length -desc|select fullname -f 5"', intern=TRUE)
For more information see:
http://stat.ethz.ch/R-manual/R-patched/library/base/html/system.html
In particular:
If
intern = TRUE, a character vector giving the output of the command, one line per character string.
and
If
intern = FALSE, the return value is an error code (0 for success),
var, I got var [1] 0 typeof(var) [1] "integer" How to assign the output content to a var?