Change size of move an existing file

Change size of an existing file (on some platforms sparse files are used) or move file to other name and/or location.

file.resize(path, size)
  file.move(from, to)

Arguments

path

file path (on windows it uses a 'windows' backslash path!)

size

new filesize in bytes as double

from

old file path

to

new file path

Value

logical scalar repesenting the success of this operation

Details

file.resize can enlarge or shrink the file. When enlarged, the file is filled up with zeros. Some platform implementations feature sparse files, so that this operation is very fast. We have tested:

  • Ubuntu Linux 8, i386

  • FreeBSD 7, i386

  • Gentoo Linux Virtual-Server, i386

  • Gentoo Linux, x86_64

  • Windows XP

The following work but do not support sparse files

  • Mac OS X 10.5, i386

  • Mac OS X 10.4, PPC

file.move tries to file.rename, if this fails (e.g. across file systems) the file is copied to the new location and the old file is removed, see file.copy and file.remove.

Author

Daniel Adler

Examples

 x <- tempfile()
 newsize <- 23       # resize and size to 23 bytes.
 file.resize(x, newsize)
#> [1] TRUE
 file.info(x)$size == newsize
#> [1] TRUE
 if (FALSE) { # \dontrun{
   newsize <- 8*(2^30) # create new file and size to 8 GB.
   file.resize(x, newsize)
   file.info(x)$size == newsize
 } # }
 y <- tempfile()
 file.move(x,y)
#> [1] TRUE
 file.remove(y)
#> [1] TRUE