rtrash.R

#!/usr/bin/Rscript --vanilla

### rtrash.R (version 2011-05-20)
### 2011, Sven Hartenstein <mail@svenhartenstein.de>
###
### This program is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
###
### This script is a poor man's way of deleting from libtrash's trash
### bin. It is an alternative to strash which comes with libtrash 3.2
### and which is not working on my computer (and according to the www
### not on the computer of some other people; my guess is that under
### some circumstances access times are not set reliably). rtrash.R is
### written in the R language and R must be installed to use it. (It
### would surely be more elegant to use a different programming
### language, but nobody tought me python yet.) You can find R at
### http://www.r-project.org.
###
### rtrash.R deletes files from trash which are in the trash longer
### than X days. While strash is much more intelligent and uses the
### access times (or so) for evaluating the files' duration of stay in
### the trash, rtrash.R records the arrival in the trash itself.
### Therefore, rtrash.R works even if access times are not reliable.
### The disadvantage of rtrash.R is that it does not know when files
### in the trash were actually put there and thus must be run
### regularly to check whether new files are in the trash and record
### their filenames for future deletion. If the trash holds many
### files, the record file (a simple CSV file) may get large. rtrash.R
### should usually be run regularly and automatically, e.g. by cron. I
### run it automatically whenever I log in.
###
### If you find this script useful, please let me know!
###
### Usage:
###   rtrash.R [option...]
###
### Options: (You can NOT combine like '-nd', use '-n -d' instead!)
###   -d NUM     Delete remembered files in trash older than NUM days.
###              Caution, '-d 0' will delete all files in the trash!
###   -n         Do nothing, just report. Implies -v.
###   -s         Remember new files in trash for future deletion.
###   -v         Verbose.
###
### Examples:
###   rtrash.R -s -d 30
###       Record new files in trash and delete files recorded 30 or
###       more days ago, without any output.
###   rtrash.R -n -d 7
###       Print one line for each file that has been recorded 7 or
###       more days ago, without actually deleting.


### Configuration

trashDir <- "~/.Trash"
recordFile <- "~/.rtrash.csv"

### End of configuration.

args <- commandArgs(trailingOnly=TRUE)
if (!("-d" %in% args | "-s" %in% args)) stop("Neither argument -d nor -s given. I do nothing.")

is.wholenumber <- function(x, tol=.Machine$double.eps^0.5)  abs(x - round(x)) < tol

## Set trash (the actual list of files in trash) and record (the
## recorded filenames with date)
trash <- list.files(path=trashDir, all.files=TRUE, full.names=TRUE, recursive=TRUE)
if (file.exists(recordFile)) {
  record <- read.csv(recordFile, colClasses=c("Date", "character"))
  ## Delete entries in record that are (for some reason) not in trash:
  record <- record[record[["filename"]] %in% trash, ]
} else {
  record <- data.frame()
}

## Settings for argument -n (dry run)
if ("-n" %in% args) {
  dryrun <- TRUE
  drystr <- " WOULD:"
  args <- append(args, "-v")
} else {
  dryrun <- FALSE
  drystr <- ""
}

## Deletion
if ("-d" %in% args && nrow(record) >= 1) {
  days <- as.numeric(args[match("-d", args)+1])
  if (!is.wholenumber(days)) stop("Argument -d is not a valid number!")
  del <- (as.integer(Sys.Date())-as.integer(as.Date(record[["rememberdate"]]))) >= days
  for (file in record[["filename"]][del]) {
    ## We do not use file.remove() because the file could end up in
    ## the trash again.
    if ("-v" %in% args) cat(drystr, "Deleting", file, "\n")
    if (!dryrun) system(paste("TRASH_OFF=YES rm \"", file, "\"", sep=""))
  }
  if (!dryrun && any(del)) {
    ## Delete empty directories:
    system(paste("find ",path.expand(trashDir)," -mindepth 1 -type d -empty -delete", sep=""))
  }
  ## Update trash
  trash <- trash[ !(trash %in% record[["filename"]][del]) ]
  ## Update record
  record <- record[!del, ]
}

## Recording
if ("-s" %in% args) {
  filenames <- trash[!(trash %in% record[["filename"]])]
  newRecord <- data.frame(rememberdate=rep(Sys.Date(), times=length(filenames)),
                          filename=filenames)
  if ("-v" %in% args) cat(drystr, "Remembering", length(filenames), "new files in trash.\n")
  record <- rbind(record, newRecord)
}

## Update record file
if (!dryrun) write.csv(record, file=recordFile, row.names=FALSE)