[R] r-help:

[Ott Toomet]

Hi,

 | From: Sam McClatchie <s.mcclatchie at niwa.co.nz>
 | Date: Tue, 10 Dec 2002 10:03:48 +1300
 | 
 | Can anyone tell me what R does with local variables when they are passed
 | in a system call to a shell script?
 | 
 | e.g. I have a string as an R variable called tripcode. I want to pass
 | this variable in a system call to a local bash script calling gmt
 | (Generic Mapping Tool) functions:
 | 
 |   system("source map_acoustic_transects_and_trawls.gmt", tripcode)

You are missing paste() here.  Look ?paste.
E.g.

a <- "-l"
> system("ls", a)
10-doc		     funktsioonid.R~	    lave-spell	       Overview.dvi
andmed		     gauss-analyse.tar.gz   lave-spell.tar.gz  Overview.log
artikkel2	     gauss-analyse.tar.gz~  Leifi_kirjad.txt   Overview.tex
...

> system(paste("ls", a))
total 488
drwxrwxr-x    2 otoomet  otoomet      4096 dets   5 14:19 10-doc
drwxrwxr-x    3 otoomet  otoomet      4096 nov   19 15:46 andmed
drwxrwxr-x    3 otoomet  otoomet      4096 dets   5 12:44 artikkel2
drwxrwxr-x    2 otoomet  otoomet      4096 dets   5 07:03 bilder
...

 | I think this is what is meant in Section 4.6 of Venables and Ripley(?).
 | 
 | When I ECHO the parameter passed into the bash script nothing is returned:
 | 
 | echo "TripCode" $tripcode
 | TripCode
 | 
 | Is there a way to do this efficiently without writing the string
 | variable to a file and re-reading it into the shell script?

Ott