Bash Script for deleting old backup files -

every night server creates backups every mysql database. of these files saved in folder /backup/mysql/2014-11-28. on last few months lot of folders , files have been stored in directory , reduce this.

therefore need bash script deletes every folder in given directory, except every folder created month (not in last 30 days, actual month) , except 1 backup every week (for example backup sunday). since have no clue how sunday party decided simpler keep backups 07th, 14th, 21st , the 28th.

#!/bin/bash in_array() { local haystack=${1}[@] local needle=${2} in ${!haystack};     if [[ ${i} == ${needle} ]];         return 0     fi done return 1 }  year=`date +%y` lastyear=`date +%y -d "1 year ago"` month=`date +%m` days="07 14 21 28" in $( ls ); backup_year=$(echo "${i}" | cut -d'-' -f1) backup_month=$(echo "${i}" | cut -d'-' -f2) backup_day=$(echo "${i}" | cut -d'-' -f3)  delete=false  if [[ "$backup_year" == "$year" ]];     if [[ "$backup_month" != "$month" ]];             if [ $(in_array $days "$backup_day") ];                 delete=true             fi     fi fi if [[ "$backup_year" == "$lastyear" ]];     if [[ "$backup_day" != ${days[0]} ]];         delete=true     fi fi if [ "$delete" = true ] ;     #output=`rm -v -r $i`     echo $i fi done 

the second part (backups year before) works fine, first part (for backups year) doesn't work , don't know why. found function on site, guess somehow call wrong.

edit: code using:

#!/bin/bash read year month <<<$(date "+%y %m") lastyear=$(( year-1 )) days=" 07 14 21 28 "  fn in $( ls )     if   ([ "${fn:0:4}" = "$year" ] &&     [ "${fn:5:2}" != "$month" ] &&     [ "${days/ ${fn:8:2} /}" = "$days" ]) || ([ "${fn:0:4}" = "$lastyear" ] &&     [ "${fn:8:2}" != ${days:1:2} ])              #output=`rm -v -r $fn`          echo "$fn"    fi done 

#!/bin/bash read year month <<<$(date "+%y %m") lastyear=$(( year-1 )) days=" 07 14 21 28 "  fn in $( ls )      delete=false       if   [ "${fn:0:7}" = "$year-$month" ] &&           [ "${days/ ${fn:8:2} /}" != "$days" ]                delete=true      elif [ "${fn:0:4}" = "$lastyear" ] &&           [ "${fn:8:2}" != ${days:1:2} ]                delete=true      fi       if [ "$delete" = true ]                #output=`rm -v -r $fn`           echo "$fn"      fi done 

assuming file name matches following date format yyyy-mm-dd, instance, 2014-03-27, expression ${fn:0:7} 2014-03; ${fn:8:2} 27; ${fn:0:4} 2014.

read bash manual pages parameter expansion.

the expression ${days/ ${fn:8:2} /} checks day filename (wrapped white spaces) found in days list. equivalent echo "${days}" | grep -q "${backup_day}".

note: possible reduce commands inside for loop (join if , elif means of || , remove delete variable checking , delete variable itself) decided keep of original script.