Code to delete older backups, ordered by date

I'm very new in bash script and need to write this code.

The purpose of this code is to delete older backups depending on how old they are. The folders name is the date they were made. I think I commented everything, so the idea should be easy to get.

#!/bin/sh
#delte backups automatically

cd backup/backup_collection #make sure to be in the right directory

todate=$(date +”%Y-%m-%d”) #today

count_back=$(ls -l | grep "^d" | wc -l) #counts the number of folders in the current directory

back_names=( $( ls . ) ) #array with all filenames

for ((i=0; i<count_back; i++ ))
do
back_days[i]=$(( (todate +%s - todate +%s -d $back_names[i]) /86400 )) #this number tells us how many days ago this backup was
done

#the array with the days is already sorted from small to big

y=$((($back_days[count_back-1] + 2) / 7)) #y is the newest date, how many weeks ago

for ((i=count_back-2; i>=0; i—- ))
do
x=$((($back_days[i] + 2) / 7)) #how many weeks ago is the i-th entry

if [ x<8 ] || [ [ x>=8 ] && [ x<=26 ] && [ y-x>=2 ] ] || [ [ x>=26 ] && [ x<52 ] && [ y-x>=4 ] ] || [ [ x>=52 ] && [ y-x>=8 ] ]
then
y=$x
else
rmdir backup/backup_collection/$back_names[i] #we remove the specific folder
fi


done


The code does not work yet. For example this line is not correct I think.

back_days[i]=$(( (todate +%s - todate +%s -d $back_names[i]) /86400 ))


I tried very much. Maybe someone can help me. I would appreciate it!

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2 Answers
2

What I'm using is something like that

MAXKEEP=30
ZIPPER_EXT="gz"

find $LOG_DIR -type f -name "*.$ZIPPER_EXT" -mtime +$MAXKEEP -exec rm -rf ;


LOG_DIR is self-explaining, and I do compress (in other part of the script) my files after a certain amount of time so I'm looking for the compressed files only. So, that line do erase compressed file after 30 days. But that can be modified easily to suits your need I think.

you can use the find command

find $RAIZ/ -name "*.gz" -atime +2 -type f -print -exec rm ;


where $ RAIZ is the directory where they are.
atime is the antiquity time in days and * .gz all extension files .gz
Maybe it's not exactly what you need, but it's a start

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