linux bash backup script

Incremental and rotating linux bash backup script which keeps original folder structure and does not overwrite unchanged files. Supports multiple backup destinations and filenames containing whitespaces and non-alphanumeric characters. Uses no compression.

Setup

backup.sh

#!/bin/bash
DAYS=3

DESTINATION=(
    '/media/'"$(whoami)"'/Backup_king'
)

SOURCE=(
    '/home/'"$(whoami)"'/dev'
    '/home/share/database'
    '/home/share/txt'
    '/home/share/web'
)


####################################################################################################
#(. )( .)  (. )( .)  (. )( .)  (. )( .)  (. )( .)  (. )( .)  (. )( .)  (. )( .)  (. )( .)  (. )( .)#
####################################################################################################

copy_ () {
    fil=$1
    target=$2
    tstamp=$(stat "$fil" -c %y | cut -d "." -f1 |  sed -e  's/-//g; s/://; s/\ //g; s/:/\./')
    cp "$fil" "$target""$fil"
    echo COPY "$target""$fil"
    touch -mt $tstamp "$target""$fil"
}


for TARGET in ${DESTINATION[@]} ; do


    if [ ! -d "$TARGET" ]; then
        logger "backup storage medium not found:" "$TARGET" 
        echo ERROR
        break
    fi

    logger "backup is backing up files now:" "$TARGET"

    #rm unneeded dates
    folders_count=$(ls "$TARGET" | wc -l)
    if (( $folders_count > $DAYS )); then
        for rm_folder in $(ls "$TARGET" -t | tail -n $(( $folders_count - $DAYS )) );do
            rm -r "$TARGET"'/'"$rm_folder"
        done
    fi

    #mk todays dir
    dir_='/'$(date +"%d-%m-%y")
    if [ ! -d "$dir_" ];then
        mkdir -p "$TARGET""$dir_"
    fi

    TARGET="$TARGET""$dir_"

    #rm files from Backup
    find "$TARGET" -type f | while read files;do
        sourcefile=$(echo "$files"|sed 's|'$TARGET'||'g )
        if [ ! -f "$sourcefile" ] ;then
            rm "$TARGET""$sourcefile"
        fi
    done
    #rm dirs from Backup
    find "$TARGET" -type d| while read dir;do
        sourcefile=$(echo "$dir"|sed 's|"$TARGET"||'g )
        if [ ! -d "$sourcefile" ] ;then
            rm -r "$TARGET""$sourcefile"
        fi
    done

    for files in ${SOURCE[@]}; do
        #mkdirs on Backup
        find "$files" -type d | while read dir; do
            if [ ! -d $"TARGET""$dir" ]; then
                mkdir -p "$TARGET""$dir"
            fi
        done
        #file operations
        find "$files" -type f | while read file ; do
            if [ ! -f "$TARGET""$file" ]; then
                copy_ "$file" "$TARGET"
            else
                lm_o=$(stat "$file" -c %Y)
                lm_b=$(stat "$TARGET""$file" -c %Y)
                if [ $lm_o != $lm_b ] && [ $lm_o != $(( $lm_b + 1 )) ] && [ $lm_o != $(( $lm_b + 2 )) ];then
                    copy_ "$file" "$TARGET"
                fi
            fi 
        done

    done #SOURCE

done #TARGET

install.sh

#!/bin/sh

mkdir -p '/home/'$(whoami)'/.backup' 
cp 'backup.sh' '/home/'$(whoami)'/.backup' 
chmod +x '/home/'$(whoami)'/.backup/backup.sh'


crontab -l > '/tmp/ccron'
if grep -q "#backup" "/tmp/ccron";then
    echo "#backup cron job exists"
else
    echo "adding new cron job"
    echo '55 0-23/2 * * * /home/'$(whoami)'/.backup/backup.sh #backup' >> '/tmp/ccron'
    crontab '/tmp/ccron'
fi

rm '/tmp/ccron'