backup changed files - shell script

backupfile

#!/bin/sh

# Copyright (c) 2015 Václav Brožík
# MIT License - See the file LICENSE.

# Description: full backup changed file(s), log operations
# Syntax: backupchanged statusfile logfile destination

datetime="$(date +%Y-%m-%dT%H:%M:%S)"
backuplist="${1-backup-list}"
logfile="${2-backup.log}"
destdir="${3-backup}/$datetime"

exec 3>>"$logfile"

mkdir "$destdir" || exit 1

printf '\n=== Backing up into %s started. ===\n' "$destdir" >&3

while read file hash size ; do
    printf '%s %s - ' "$(date --rfc-3339=s)" "$file" >&3
    if test -r "$file" ; then
        newhash="$(md5sum -b "$file" | cut -d' ' -f1)"
        newsize="$(stat -c%s "$file")"
        if [ "$hash" = "$newhash" ] && [ "$size" = "$newsize" ] ; then
            printf 'unchanged\n' >&3
        else
            printf 'newhash: %s, newsize: %s, backup ' "$newhash" "$newsize" >&3
            if cp -a "$file" "$destdir" ; then
                printf 'OK\n' >&3
            else
                printf 'FAILED\n' >&3
            fi
        fi
        printf '%s %s %s\n' "$file" "$newhash" "$newsize" >&4
    else
        printf 'inacessible\n' "$file" >&3
        printf '%s inacessible\n' "$file" >&4
    fi
done <"$backuplist" 4>"$backuplist.new"

mv "$backuplist" "$backuplist~"
mv "$backuplist.new" "$backuplist"

if test "$(ls -a "$destdir" | wc -l)" -le 2 ; then
    rmdir "$destdir"
    printf 'Removed empty destination directory.\n' >&3
fi

printf '=== Backing up into %s finished. ===\n' "$destdir" >&3