Script for deleting old files in directory except latest N

I want to write a script that will clean backup directory from old files, leaving only latest N there. I also want to do it without using ls.

Yesterday I ended up with the following piece of code:

counter=0
while IFS=/ read -rd '' time file; do

        ((counter++ < ${KEEP_NUMBER:?})) && continue
        rm -f "$file"

done < <(find . -maxdepth 1 -type f -printf "%T@/%p\0" | sort -znr)

开发者_如何学PythonHowever, this isn't portable at all, as there is find -printf been used, leaving behind all the boxes without GNU extensions.

Are there any better ways to accomplish such a task?

---

It can be done relatively easily provided you have

• A shell that supports arrays (as bash does)
• Access to test (which can compare the age of 2 files)

Here's my attempt (it probably doesn't cope with spaces in filenames, but that could be fixed easily enough

#!/bin/bash

declare -a files
for file in *
do
    files[${#files[@]}]=$file
done

# Bubble sort the files from newest to oldest
declare -i i j count=${#files[@]}
while true
do
    declare -i sorted=1
    for ((i=1;i<count;i++))
    do
        let j=i-1
        if [ ${files[$j]} -ot ${files[$i]} ]
        then
            sorted=0
            f=${files[$j]}
            files[$j]=${files[$i]}
            files[$i]=$f
        fi
    done
    [ $sorted -eq 1 ] && break
done

# Delete everything except the first 5 files
for ((i=5;i<count;i++))
do
    rm "${files[$i]}"
done

---

Well, there's POSIX -newer primary to the find. It - with some minor coding - can be used to separate files by their modification time. I would have done something like taking the first file, finding the ones newer. There i have two sets - newer and older. If there are more newer files than N, i repeat the process for the newer set only, otherwise i remember the newer set, subtract this number from N and repeat the process for the older set.

Or you can use pax to create an archive, and then use -o listopt to extract modification time in the format you want, there you have all the information:)

---

http://www.google.fr/search?q=zfs

else ...

man rsnapshoot

else ...

Stop trying to reinvent a backup suite

else ...

man find | grep -- -ctime man find | grep -- -delete