main.sh

#!/usr/bin/env bash
#Split a file into multiple parts, compress and email
#Usage: ./file_backup.sh input_file, [--split 10m] [--email user@email.com] [--uncompressed] [--msx-files 16]
#[--time-start] can be given as "$(date +%s%N)/1000000" from another script to get a more accuate time.
#TODO: Time taken (for email body), maximum_file_limit


(( time_start=$(date +%s%N)/1000000 ))

#Create temp folder - https://stackoverflow.com/a/34676160/2403000
script_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
work_dir=$(mktemp -d -p "$script_dir")
if [[ ! "$work_dir" || ! -d "$work_dir" ]]; then
  echo "Error: Failed to create temp dir."
  exit 1
fi
function cleanup {
  rm -rf "$work_dir"
}
trap cleanup EXIT

source config.conf

#Parse arguments
file_path=$1

compress_file=true
max_files=8
while [ $# -ge 1 ]; do
        case "$1" in
                -- )
                    shift
                    break
                   ;;
                -e | --email )
                        email_address="$2"
                        shift
                        ;;
                -s | --split | --split-size | --split-file )
                        split_size="$2"
                        shift
                        ;;
                -fl | --file-limit | -mf | --max-files )
                        max_files="$2"
                        shift
                        ;;
                -ts | --time-start )
                        time_start="$2"
                        shift
                        ;;
                -dc | --disable-compression | -uc | --uncompressed )
                        compress_file=false
                        ;;
                -m | --message )
                        custom_message="$2"
                        ;;
                --name-override )
                        name_override="$2"
                        shift
                        ;;
                -h | --help )
                        echo "Display some help"
                        exit 0
                        ;;
        esac
        shift
done

if [ ! -z "$email_address" ] && [ -z "$SEND_ADDRESS" ]; then
    echo "Warning: SEND_ADDRESS not defined in config. Using default."
fi

base_file=$(basename "$file_path")

original_file="$base_file"

new_location="$work_dir/$original_file"

#Copy and compress
if [ "$compress_file" = true ]; then
    cp "$file_path" "$new_location"
    gzip "$new_location"
    file_path="$new_location.gz"
    original_file=$(basename "$file_path")
    new_location="$work_dir/$original_file"
fi

#Split the file
if [ -z "$split_size" ] || [ "$split_size" -eq 0 ];
then
    cp "$file_path" "$new_location.0"
else
    split --bytes "$split_size" --numeric-suffixes --suffix-length 1 "$file_path" "$new_location."
fi

#End timer
(( time_end=$(date +%s%N)/1000000 ))
(( time_elapsed=time_end-time_start ))

#Process each file
index=1
num_files=$(find "$work_dir" -iname "$original_file.*" -type f -printf '.' | wc -c)
if  [ "$num_files" -gt "$max_files" ]; then
    echo "Error: Too many split files ($num_files). Use --max-files to override this limit."
elif [ "$num_files" -eq 0 ]; then
    echo "Error: File doesn't exist."
else
    for file in $new_location.*
    do  
        echo "Processing: $file"

        #Remove .0 if there is only 1 part
        if [ "$num_files" -le 1 ]; then
            mv "$file" "$new_location"
            file="$new_location"
        fi
        
        #Send email
        if [ ! -z "$email_address" ]; then
            
            echo "Sending $(basename "$file") to $email_address... $index/$num_files"
            
            #Override name
            file_text="$base_file"
            if [ ! -z "$name_override" ]; then
                file_text="$name_override"
            fi
            
            #Generate email subject and body
            subject="Backup of $file_text"
            if [ "$num_files" -gt 1 ]; then
                subject="$subject (Part $index)"
            fi
            message="Preparation of the file took ${time_elapsed}ms."
            if [ ! -z "$custom_message" ]; then
                message="$custom_message\n\n$message"
            fi
            
            #Get email from config if possible, otherwise fallback to default
            if [ ! -z "$SEND_ADDRESS" ]; then
                header="my_hdr From:$SEND_ADDRESS"
            fi
            
            echo -e "$message" | mutt -a "$file" -s "$subject" -e "$header" -- "$email_address"
        fi
        
        (( index++ ))
    done
fi