Download NASA Astronomy Picture Of Day media. (Bash version)

apod.sh

#!/bin/bash

# Constants
TMPDIR=/tmp/apod
LISTFILE=$TMPDIR/list.html
REMOTEPREFIX=http://antwrp.gsfc.nasa.gov/apod/

# Functions
function parse_page() {
    printf "Downloading photo page %s...\n" $1
    page=$TMPDIR/$1
    curl -s $REMOTEPREFIX/$1 -o $page
    regex=\[\^\"\]\*\\.\\\(jpg\\\|png\\\|gif\\\|avi\\\|mov\\\|mp4\\\|m4v\\\)

    small=`grep -i img $page | grep -e $regex -o`
    big=`grep -e  href=\"$regex $page | grep -e $regex -o`

    if ! [ -f $SMALLDIR/`basename $small` ];then
        printf "Downloading small photo %s...\n" `basename $small`
        curl -s $REMOTEPREFIX/$small -o $SMALLDIR/`basename $small`
    fi
    
    if ! [ -f $BIGDIR/`basename $big` ];then
        printf "Downloading big photo %s...\n" `basename $big`
        curl -s $REMOTEPREFIX/$big -o $BIGDIR/`basename $big`
    fi
}

function parse_list() {
    for i in $(grep -e 'ap\w\{5,\}\.html' $LISTFILE -o)
    do
        printf "Parsing page %s...\n" $i
        parse_page $i
    done
}

# Judge if curl exists
which -s curl
if [ $? -ne 0 ];then
    printf "You must install curl first.\n"
    exit 1
fi

# Show Start up Message
function print_info() {
    clear
    printf "*************************************************************\n\n"
    printf "About to download NASA Astronomy Photo of Day Archive.\n"
    printf "It could take a very long time to download over 10,000 files.\n"
    printf "So, Please be patient.\n\n"
    printf "We recommend you to run this script on the background.\n\n"
    printf "Press ENTER to continue, CTRL-c to stop.\n\n"
    printf "*************************************************************\n"
    read
    clear
}


# Start to process 

if [ $# -ne 0 ] && ([ $1='-h' ] || [ $1='--help' ]);then
    printf "\n\tUsage: %s [-h|--help|DOWNLOAD_DIR]\n\n"
    printf "\tIf you do not specify download dir, \n"
    printf "\tphoto will download to current dir.\n\n"
    exit 0
fi

# Make a temp dir
mkdir -p $TMPDIR

printf "Make directories for hold photos...\n"
# Make big and small dir
if [ $# -ne 0 ] && [ -d $1 ];then
    BIGDIR=$1/big
    SMALLDIR=$1/small
else
    BIGDIR=$PWD/big
    SMALLDIR=$PWD/small
fi

print_info
mkdir -p $BIGDIR
mkdir -p $SMALLDIR

printf "Downloading index page...\n"
# Download the list html to temp dir as name list.html
if ! [ -f $LISTFILE ];then
    curl -s ${REMOTEPREFIX}/archivepix.html -o $LISTFILE
fi
# Parse it.
parse_list

printf "\nDone.\n"