How to write a shell script to back up data on a VPS to a Dropbox network disk _linux Shell

See someone using Dropbox backup site data, so today also tried, remember a python script, this is a bash script, using the Dropbox API to upload the download, very convenient, the script address is dropbox-uploader/ Dropbox_uploader.sh at Master Andreafabrizi/dropbox-uploader GitHub, thank the author for sharing this script.

You can download dropbox_uploader.sh to git, address: https://github.com/andreafabrizi/Dropbox-Uploader
Alternatively, you can copy the code directly, save it as a dropbox_uploader.sh, and note that copying is best copied to a text editor, like notepad++.

#!/usr/bin/env bash
#
# Dropbox Uploader
#
# Copyright (C) 2010-2014 Andrea Fabrizi <andrea.fabrizi@gmail.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#

#Default configuration file
CONFIG_FILE=~/.dropbox_uploader

#Default chunk size in Mb for the upload process
#It is recommended to increase this value only if you have enough free space on your /tmp partition
#Lower values may increase the number of http requests
CHUNK_SIZE=4

#Curl location
#If not set, curl will be searched into the $PATH
#CURL_BIN="/usr/bin/curl"

#Default values
TMP_DIR="/tmp"
DEBUG=0
QUIET=0
SHOW_PROGRESSBAR=0
SKIP_EXISTING_FILES=0
ERROR_STATUS=0

#Don't edit these...
API_REQUEST_TOKEN_URL="https://api.dropbox.com/1/oauth/request_token"
API_USER_AUTH_URL="https://www2.dropbox.com/1/oauth/authorize"
API_ACCESS_TOKEN_URL="https://api.dropbox.com/1/oauth/access_token"
API_CHUNKED_UPLOAD_URL="https://api-content.dropbox.com/1/chunked_upload"
API_CHUNKED_UPLOAD_COMMIT_URL="https://api-content.dropbox.com/1/commit_chunked_upload"
API_UPLOAD_URL="https://api-content.dropbox.com/1/files_put"
API_DOWNLOAD_URL="https://api-content.dropbox.com/1/files"
API_DELETE_URL="https://api.dropbox.com/1/fileops/delete"
API_MOVE_URL="https://api.dropbox.com/1/fileops/move"
API_COPY_URL="https://api.dropbox.com/1/fileops/copy"
API_METADATA_URL="https://api.dropbox.com/1/metadata"
API_INFO_URL="https://api.dropbox.com/1/account/info"
API_MKDIR_URL="https://api.dropbox.com/1/fileops/create_folder"
API_SHARES_URL="https://api.dropbox.com/1/shares"
APP_CREATE_URL="https://www2.dropbox.com/developers/apps"
RESPONSE_FILE="$TMP_DIR/du_resp_$RANDOM"
CHUNK_FILE="$TMP_DIR/du_chunk_$RANDOM"
TEMP_FILE="$TMP_DIR/du_tmp_$RANDOM"
BIN_DEPS="sed basename date grep stat dd mkdir"
VERSION="0.14"

umask 077

#Check the shell
if [ -z "$BASH_VERSION" ]; then
  echo -e "Error: this script requires the BASH shell!"
  exit 1
fi

shopt -s nullglob #Bash allows filename patterns which match no files to expand to a null string, rather than themselves
shopt -s dotglob #Bash includes filenames beginning with a "." in the results of filename expansion

#Look for optional config file parameter
while getopts ":qpskdf:" opt; do
  case $opt in

  f)
   CONFIG_FILE=$OPTARG
  ;;

  d)
   DEBUG=1
  ;;

  q)
   QUIET=1
  ;;

  p)
   SHOW_PROGRESSBAR=1
  ;;

  k)
   CURL_ACCEPT_CERTIFICATES="-k"
  ;;

  s)
   SKIP_EXISTING_FILES=1
  ;;

  \?)
   echo "Invalid option: -$OPTARG" >&2
   exit 1
  ;;

  :)
   echo "Option -$OPTARG requires an argument." >&2
   exit 1
  ;;

 esac
done

if [[ $DEBUG != 0 ]]; then
  echo $VERSION
  set -x
  RESPONSE_FILE="$TMP_DIR/du_resp_debug"
fi

if [[ $CURL_BIN == "" ]]; then
  BIN_DEPS="$BIN_DEPS curl"
  CURL_BIN="curl"
fi

#Dependencies check
which $BIN_DEPS > /dev/null
if [[ $? != 0 ]]; then
  for i in $BIN_DEPS; do
    which $i > /dev/null ||
      NOT_FOUND="$i $NOT_FOUND"
  done
  echo -e "Error: Required program could not be found: $NOT_FOUND"
  exit 1
fi

#Check if readlink is installed and supports the -m option
#It's not necessary, so no problem if it's not installed
which readlink > /dev/null
if [[ $? == 0 && $(readlink -m "//test" 2> /dev/null) == "/test" ]]; then
  HAVE_READLINK=1
else
  HAVE_READLINK=0
fi

#Forcing to use the builtin printf, if it's present, because it's better
#otherwise the external printf program will be used
#Note that the external printf command can cause character encoding issues!
builtin printf "" 2> /dev/null
if [[ $? == 0 ]]; then
  PRINTF="builtin printf"
  PRINTF_OPT="-v o"
else
  PRINTF=$(which printf)
  if [[ $? != 0 ]]; then
    echo -e "Error: Required program could not be found: printf"
  fi
  PRINTF_OPT=""
fi

#Print the message based on $QUIET variable
function print
{
  if [[ $QUIET == 0 ]]; then
	  echo -ne "$1";
  fi
}

#Returns unix timestamp
function utime
{
  echo $(date +%s)
}

#Remove temporary files
function remove_temp_files
{
  if [[ $DEBUG == 0 ]]; then
    rm -fr "$RESPONSE_FILE"
    rm -fr "$CHUNK_FILE"
    rm -fr "$TEMP_FILE"
  fi
}

#Returns the file size in bytes
# generic GNU Linux: linux-gnu
# windows cygwin:  cygwin
# raspberry pi:   linux-gnueabihf
# macosx:      darwin10.0
# freebsd:      FreeBSD
# qnap:       linux-gnueabi
# iOS:        darwin9
function file_size
{
  #Some embedded linux devices
  if [[ $OSTYPE == "linux-gnueabi" || $OSTYPE == "linux-gnu" ]]; then
    stat -c "%s" "$1"
    return

  #Generic Unix
  elif [[ ${OSTYPE:0:5} == "linux" || $OSTYPE == "cygwin" || ${OSTYPE:0:7} == "solaris" ]]; then
    stat --format="%s" "$1"
    return

  #BSD, OSX and other OSs
  else
    stat -f "%z" "$1"
    return
  fi
}

#Usage
function usage
{
  echo -e "Dropbox Uploader v$VERSION"
  echo -e "Andrea Fabrizi - andrea.fabrizi@gmail.com\n"
  echo -e "Usage: $0 COMMAND [PARAMETERS]..."
  echo -e "\nCommands:"

  echo -e "\t upload  <LOCAL_FILE/DIR ...> <REMOTE_FILE/DIR>"
  echo -e "\t download <REMOTE_FILE/DIR> [LOCAL_FILE/DIR]"
  echo -e "\t delete  <REMOTE_FILE/DIR>"
  echo -e "\t move   <REMOTE_FILE/DIR> <REMOTE_FILE/DIR>"
  echo -e "\t copy   <REMOTE_FILE/DIR> <REMOTE_FILE/DIR>"
  echo -e "\t mkdir  <REMOTE_DIR>"
  echo -e "\t list   [REMOTE_DIR]"
  echo -e "\t share  <REMOTE_FILE>"
  echo -e "\t info"
  echo -e "\t unlink"

  echo -e "\nOptional parameters:"
  echo -e "\t-f <FILENAME> Load the configuration file from a specific file"
  echo -e "\t-s      Skip already existing files when download/upload. Default: Overwrite"
  echo -e "\t-d      Enable DEBUG mode"
  echo -e "\t-q      Quiet mode. Don't show messages"
  echo -e "\t-p      Show cURL progress meter"
  echo -e "\t-k      Doesn't check for SSL certificates (insecure)"

  echo -en "\nFor more info and examples, please see the README file.\n\n"
  remove_temp_files
  exit 1
}

#Check the curl exit code
function check_http_response
{
  CODE=$?

  #Checking curl exit code
  case $CODE in

    #OK
    0)

    ;;

    #Proxy error
    5)
      print "\nError: Couldn't resolve proxy. The given proxy host could not be resolved.\n"

      remove_temp_files
      exit 1
    ;;

    #Missing CA certificates
    60|58)
      print "\nError: cURL is not able to performs peer SSL certificate verification.\n"
      print "Please, install the default ca-certificates bundle.\n"
      print "To do this in a Debian/Ubuntu based system, try:\n"
      print " sudo apt-get install ca-certificates\n\n"
      print "If the problem persists, try to use the -k option (insecure).\n"

      remove_temp_files
      exit 1
    ;;

    6)
      print "\nError: Couldn't resolve host.\n"

      remove_temp_files
      exit 1
    ;;

    7)
      print "\nError: Couldn't connect to host.\n"

      remove_temp_files
      exit 1
    ;;

  esac

  #Checking response file for generic errors
  if grep -q "HTTP/1.1 400" "$RESPONSE_FILE"; then
    ERROR_MSG=$(sed -n -e 's/{"error": "\([^"]*\)"}/\1/p' "$RESPONSE_FILE")

    case $ERROR_MSG in
       *access?attempt?failed?because?this?app?is?not?configured?to?have*)
        echo -e "\nError: The Permission type/Access level configured doesn't match the DropBox App settings!\nPlease run \"$0 unlink\" and try again."
        exit 1
      ;;
    esac

  fi

}

#Urlencode
function urlencode
{
  local string="${1}"
  local strlen=${#string}
  local encoded=""

  for (( pos=0 ; pos<strlen ; pos++ )); do
    c=${string:$pos:1}
    case "$c" in
      [-_.~a-zA-Z0-9] ) o="${c}" ;;
      * ) $PRINTF $PRINTF_OPT '%%%02x' "'$c"
    esac
    encoded+="${o}"
  done

  echo "$encoded"
}

function normalize_path
{
  path=$(echo -e "$1")
  if [[ $HAVE_READLINK == 1 ]]; then
    readlink -m "$path"
  else
    echo "$path"
  fi
}

#Check if it's a file or directory
#Returns FILE/DIR/ERR
function db_stat
{
  local FILE=$(normalize_path "$1")

  #Checking if it's a file or a directory
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" "$API_METADATA_URL/$ACCESS_LEVEL/$(urlencode "$FILE")?oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM" 2> /dev/null
  check_http_response

  #Even if the file/dir has been deleted from DropBox we receive a 200 OK response
  #So we must check if the file exists or if it has been deleted
  if grep -q "\"is_deleted\":" "$RESPONSE_FILE"; then
    local IS_DELETED=$(sed -n 's/.*"is_deleted":.\([^,]*\).*/\1/p' "$RESPONSE_FILE")
  else
    local IS_DELETED="false"
  fi

  #Exits...
  grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"
  if [[ $? == 0 && $IS_DELETED != "true" ]]; then

    local IS_DIR=$(sed -n 's/^\(.*\)\"contents":.\[.*/\1/p' "$RESPONSE_FILE")

    #It's a directory
    if [[ $IS_DIR != "" ]]; then
      echo "DIR"
    #It's a file
    else
      echo "FILE"
    fi

  #Doesn't exists
  else
    echo "ERR"
  fi
}

#Generic upload wrapper around db_upload_file and db_upload_dir functions
#$1 = Local source file/dir
#$2 = Remote destination file/dir
function db_upload
{
  local SRC=$(normalize_path "$1")
  local DST=$(normalize_path "$2")

  #Checking if the file/dir exists
  if [[ ! -e $SRC && ! -d $SRC ]]; then
    print " > No such file or directory: $SRC\n"
    ERROR_STATUS=1
    return
  fi

  #Checking if the file/dir has read permissions
  if [[ ! -r $SRC ]]; then
    print " > Error reading file $SRC: permission denied\n"
    ERROR_STATUS=1
    return
  fi

  #Checking if DST it's a folder or if it doesn' exists (in this case will be the destination name)
  TYPE=$(db_stat "$DST")
  if [[ $TYPE == "DIR" ]]; then
    local filename=$(basename "$SRC")
    DST="$DST/$filename"
  fi

  #It's a directory
  if [[ -d $SRC ]]; then
    db_upload_dir "$SRC" "$DST"

  #It's a file
  elif [[ -e $SRC ]]; then
    db_upload_file "$SRC" "$DST"

  #Unsupported object...
  else
    print " > Skipping not regular file \"$SRC\"\n"
  fi
}

#Generic upload wrapper around db_chunked_upload_file and db_simple_upload_file
#The final upload function will be choosen based on the file size
#$1 = Local source file
#$2 = Remote destination file
function db_upload_file
{
  local FILE_SRC=$(normalize_path "$1")
  local FILE_DST=$(normalize_path "$2")

  shopt -s nocasematch

  #Checking not allowed file names
  basefile_dst=$(basename "$FILE_DST")
  if [[ $basefile_dst == "thumbs.db" || \
     $basefile_dst == "desktop.ini" || \
     $basefile_dst == ".ds_store" || \
     $basefile_dst == "icon\r" || \
     $basefile_dst == ".dropbox" || \
     $basefile_dst == ".dropbox.attr" \
    ]]; then
    print " > Skipping not allowed file name \"$FILE_DST\"\n"
    return
  fi

  shopt -u nocasematch

  #Checking file size
  FILE_SIZE=$(file_size "$FILE_SRC")

  #Checking if the file already exists
  TYPE=$(db_stat "$FILE_DST")
  if [[ $TYPE != "ERR" && $SKIP_EXISTING_FILES == 1 ]]; then
    print " > Skipping already existing file \"$FILE_DST\"\n"
    return
  fi

  if [[ $FILE_SIZE -gt 157286000 ]]; then
    #If the file is greater than 150Mb, the chunked_upload API will be used
    db_chunked_upload_file "$FILE_SRC" "$FILE_DST"
  else
    db_simple_upload_file "$FILE_SRC" "$FILE_DST"
  fi

}

#Simple file upload
#$1 = Local source file
#$2 = Remote destination file
function db_simple_upload_file
{
  local FILE_SRC=$(normalize_path "$1")
  local FILE_DST=$(normalize_path "$2")

  if [[ $SHOW_PROGRESSBAR == 1 && $QUIET == 0 ]]; then
    CURL_PARAMETERS="--progress-bar"
    LINE_CR="\n"
  else
    CURL_PARAMETERS="-s"
    LINE_CR=""
  fi

  print " > Uploading \"$FILE_SRC\" to \"$FILE_DST\"... $LINE_CR"
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES $CURL_PARAMETERS -i --globoff -o "$RESPONSE_FILE" --upload-file "$FILE_SRC" "$API_UPLOAD_URL/$ACCESS_LEVEL/$(urlencode "$FILE_DST")?oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM"
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then
    print "DONE\n"
  else
    print "FAILED\n"
    print "An error occurred requesting /upload\n"
    ERROR_STATUS=1
  fi
}

#Chunked file upload
#$1 = Local source file
#$2 = Remote destination file
function db_chunked_upload_file
{
  local FILE_SRC=$(normalize_path "$1")
  local FILE_DST=$(normalize_path "$2")

  print " > Uploading \"$FILE_SRC\" to \"$FILE_DST\""

  local FILE_SIZE=$(file_size "$FILE_SRC")
  local OFFSET=0
  local UPLOAD_ID=""
  local UPLOAD_ERROR=0
  local CHUNK_PARAMS=""

  #Uploading chunks...
  while ([[ $OFFSET != $FILE_SIZE ]]); do

    let OFFSET_MB=$OFFSET/1024/1024

    #Create the chunk
    dd if="$FILE_SRC" of="$CHUNK_FILE" bs=1048576 skip=$OFFSET_MB count=$CHUNK_SIZE 2> /dev/null

    #Only for the first request these parameters are not included
    if [[ $OFFSET != 0 ]]; then
      CHUNK_PARAMS="upload_id=$UPLOAD_ID&offset=$OFFSET"
    fi

    #Uploading the chunk...
    $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --upload-file "$CHUNK_FILE" "$API_CHUNKED_UPLOAD_URL?$CHUNK_PARAMS&oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM" 2> /dev/null
    check_http_response

    #Check
    if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then
      print "."
      UPLOAD_ERROR=0
      UPLOAD_ID=$(sed -n 's/.*"upload_id": *"*\([^"]*\)"*.*/\1/p' "$RESPONSE_FILE")
      OFFSET=$(sed -n 's/.*"offset": *\([^}]*\).*/\1/p' "$RESPONSE_FILE")
    else
      print "*"
      let UPLOAD_ERROR=$UPLOAD_ERROR+1

      #On error, the upload is retried for max 3 times
      if [[ $UPLOAD_ERROR -gt 2 ]]; then
        print " FAILED\n"
        print "An error occurred requesting /chunked_upload\n"
        ERROR_STATUS=1
        return
      fi
    fi

  done

  UPLOAD_ERROR=0

  #Commit the upload
  while (true); do

    $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --data "upload_id=$UPLOAD_ID&oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM" "$API_CHUNKED_UPLOAD_COMMIT_URL/$ACCESS_LEVEL/$(urlencode "$FILE_DST")" 2> /dev/null
    check_http_response

    #Check
    if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then
      print "."
      UPLOAD_ERROR=0
      break
    else
      print "*"
      let UPLOAD_ERROR=$UPLOAD_ERROR+1

      #On error, the commit is retried for max 3 times
      if [[ $UPLOAD_ERROR -gt 2 ]]; then
        print " FAILED\n"
        print "An error occurred requesting /commit_chunked_upload\n"
        ERROR_STATUS=1
        return
      fi
    fi

  done

  print " DONE\n"
}

#Directory upload
#$1 = Local source dir
#$2 = Remote destination dir
function db_upload_dir
{
  local DIR_SRC=$(normalize_path "$1")
  local DIR_DST=$(normalize_path "$2")

  #Creatig remote directory
  db_mkdir "$DIR_DST"

  for file in "$DIR_SRC/"*; do
    db_upload "$file" "$DIR_DST"
  done
}

#Returns the free space on DropBox in bytes
function db_free_quota
{
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --data "oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM" "$API_INFO_URL" 2> /dev/null
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then

    quota=$(sed -n 's/.*"quota": \([0-9]*\).*/\1/p' "$RESPONSE_FILE")
    used=$(sed -n 's/.*"normal": \([0-9]*\).*/\1/p' "$RESPONSE_FILE")
    let free_quota=$quota-$used
    echo $free_quota

  else
    echo 0
  fi
}

#Generic download wrapper
#$1 = Remote source file/dir
#$2 = Local destination file/dir
function db_download
{
  local SRC=$(normalize_path "$1")
  local DST=$(normalize_path "$2")

  TYPE=$(db_stat "$SRC")

  #It's a directory
  if [[ $TYPE == "DIR" ]]; then

    #If the DST folder is not specified, I assume that is the current directory
    if [[ $DST == "" ]]; then
      DST="."
    fi

    #Checking if the destination directory exists
    if [[ ! -d $DST ]]; then
      local basedir=""
    else
      local basedir=$(basename "$SRC")
    fi

    local DEST_DIR=$(normalize_path "$DST/$basedir")
    print " > Downloading \"$SRC\" to \"$DEST_DIR\"... \n"
    print " > Creating local directory \"$DEST_DIR\"... "
    mkdir -p "$DEST_DIR"

    #Check
    if [[ $? == 0 ]]; then
      print "DONE\n"
    else
      print "FAILED\n"
      ERROR_STATUS=1
      return
    fi

    #Extracting directory content [...]
    #and replacing "}, {" with "}\n{"
    #I don't like this piece of code... but seems to be the only way to do this with SED, writing a portable code...
    local DIR_CONTENT=$(sed -n 's/.*: \[{\(.*\)/\1/p' "$RESPONSE_FILE" | sed 's/}, *{/}\
{/g')

    #Extracting files and subfolders
    TMP_DIR_CONTENT_FILE="${RESPONSE_FILE}_$RANDOM"
    echo "$DIR_CONTENT" | sed -n 's/.*"path": *"\([^"]*\)",.*"is_dir": *\([^"]*\),.*/\1:\2/p' > $TMP_DIR_CONTENT_FILE

    #For each entry...
    while read -r line; do

      local FILE=${line%:*}
      local TYPE=${line#*:}

      #Removing unneeded /
      FILE=${FILE##*/}

      if [[ $TYPE == "false" ]]; then
        db_download_file "$SRC/$FILE" "$DEST_DIR/$FILE"
      else
        db_download "$SRC/$FILE" "$DEST_DIR"
      fi

    done < $TMP_DIR_CONTENT_FILE

    rm -fr $TMP_DIR_CONTENT_FILE

  #It's a file
  elif [[ $TYPE == "FILE" ]]; then

    #Checking DST
    if [[ $DST == "" ]]; then
      DST=$(basename "$SRC")
    fi

    #If the destination is a directory, the file will be download into
    if [[ -d $DST ]]; then
      DST="$DST/$SRC"
    fi

    db_download_file "$SRC" "$DST"

  #Doesn't exists
  else
    print " > No such file or directory: $SRC\n"
    ERROR_STATUS=1
    return
  fi
}

#Simple file download
#$1 = Remote source file
#$2 = Local destination file
function db_download_file
{
  local FILE_SRC=$(normalize_path "$1")
  local FILE_DST=$(normalize_path "$2")

  if [[ $SHOW_PROGRESSBAR == 1 && $QUIET == 0 ]]; then
    CURL_PARAMETERS="--progress-bar"
    LINE_CR="\n"
  else
    CURL_PARAMETERS="-s"
    LINE_CR=""
  fi

  #Checking if the file already exists
  if [[ -e $FILE_DST && $SKIP_EXISTING_FILES == 1 ]]; then
    print " > Skipping already existing file \"$FILE_DST\"\n"
    return
  fi

  #Creating the empty file, that for two reasons:
  #1) In this way I can check if the destination file is writable or not
  #2) Curl doesn't automatically creates files with 0 bytes size
  dd if=/dev/zero of="$FILE_DST" count=0 2> /dev/null
  if [[ $? != 0 ]]; then
    print " > Error writing file $FILE_DST: permission denied\n"
    ERROR_STATUS=1
    return
  fi

  print " > Downloading \"$FILE_SRC\" to \"$FILE_DST\"... $LINE_CR"
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES $CURL_PARAMETERS --globoff -D "$RESPONSE_FILE" -o "$FILE_DST" "$API_DOWNLOAD_URL/$ACCESS_LEVEL/$(urlencode "$FILE_SRC")?oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM"
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then
    print "DONE\n"
  else
    print "FAILED\n"
    rm -fr "$FILE_DST"
    ERROR_STATUS=1
    return
  fi
}

#Prints account info
function db_account_info
{
  print "Dropbox Uploader v$VERSION\n\n"
  print " > Getting info... "
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --data "oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM" "$API_INFO_URL" 2> /dev/null
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then

    name=$(sed -n 's/.*"display_name": "\([^"]*\).*/\1/p' "$RESPONSE_FILE")
    echo -e "\n\nName:\t$name"

    uid=$(sed -n 's/.*"uid": \([0-9]*\).*/\1/p' "$RESPONSE_FILE")
    echo -e "UID:\t$uid"

    email=$(sed -n 's/.*"email": "\([^"]*\).*/\1/p' "$RESPONSE_FILE")
    echo -e "Email:\t$email"

    quota=$(sed -n 's/.*"quota": \([0-9]*\).*/\1/p' "$RESPONSE_FILE")
    let quota_mb=$quota/1024/1024
    echo -e "Quota:\t$quota_mb Mb"

    used=$(sed -n 's/.*"normal": \([0-9]*\).*/\1/p' "$RESPONSE_FILE")
    let used_mb=$used/1024/1024
    echo -e "Used:\t$used_mb Mb"

    let free_mb=($quota-$used)/1024/1024
    echo -e "Free:\t$free_mb Mb"

    echo ""

  else
    print "FAILED\n"
    ERROR_STATUS=1
  fi
}

#Account unlink
function db_unlink
{
  echo -ne "Are you sure you want unlink this script from your Dropbox account? [y/n]"
  read answer
  if [[ $answer == "y" ]]; then
    rm -fr "$CONFIG_FILE"
    echo -ne "DONE\n"
  fi
}

#Delete a remote file
#$1 = Remote file to delete
function db_delete
{
  local FILE_DST=$(normalize_path "$1")

  print " > Deleting \"$FILE_DST\"... "
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --data "oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM&root=$ACCESS_LEVEL&path=$(urlencode "$FILE_DST")" "$API_DELETE_URL" 2> /dev/null
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then
    print "DONE\n"
  else
    print "FAILED\n"
    ERROR_STATUS=1
  fi
}

#Move/Rename a remote file
#$1 = Remote file to rename or move
#$2 = New file name or location
function db_move
{
  local FILE_SRC=$(normalize_path "$1")
  local FILE_DST=$(normalize_path "$2")

  TYPE=$(db_stat "$FILE_DST")

  #If the destination it's a directory, the source will be moved into it
  if [[ $TYPE == "DIR" ]]; then
    local filename=$(basename "$FILE_SRC")
    FILE_DST=$(normalize_path "$FILE_DST/$filename")
  fi

  print " > Moving \"$FILE_SRC\" to \"$FILE_DST\" ... "
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --data "oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM&root=$ACCESS_LEVEL&from_path=$(urlencode "$FILE_SRC")&to_path=$(urlencode "$FILE_DST")" "$API_MOVE_URL" 2> /dev/null
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then
    print "DONE\n"
  else
    print "FAILED\n"
    ERROR_STATUS=1
  fi
}

#Copy a remote file to a remote location
#$1 = Remote file to rename or move
#$2 = New file name or location
function db_copy
{
  local FILE_SRC=$(normalize_path "$1")
  local FILE_DST=$(normalize_path "$2")

  TYPE=$(db_stat "$FILE_DST")

  #If the destination it's a directory, the source will be copied into it
  if [[ $TYPE == "DIR" ]]; then
    local filename=$(basename "$FILE_SRC")
    FILE_DST=$(normalize_path "$FILE_DST/$filename")
  fi

  print " > Copying \"$FILE_SRC\" to \"$FILE_DST\" ... "
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --data "oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM&root=$ACCESS_LEVEL&from_path=$(urlencode "$FILE_SRC")&to_path=$(urlencode "$FILE_DST")" "$API_COPY_URL" 2> /dev/null
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then
    print "DONE\n"
  else
    print "FAILED\n"
    ERROR_STATUS=1
  fi
}

#Create a new directory
#$1 = Remote directory to create
function db_mkdir
{
  local DIR_DST=$(normalize_path "$1")

  print " > Creating Directory \"$DIR_DST\"... "
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --data "oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM&root=$ACCESS_LEVEL&path=$(urlencode "$DIR_DST")" "$API_MKDIR_URL" 2> /dev/null
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then
    print "DONE\n"
  elif grep -q "^HTTP/1.1 403 Forbidden" "$RESPONSE_FILE"; then
    print "ALREADY EXISTS\n"
  else
    print "FAILED\n"
    ERROR_STATUS=1
  fi
}

#List remote directory
#$1 = Remote directory
function db_list
{
  local DIR_DST=$(normalize_path "$1")

  print " > Listing \"$DIR_DST\"... "
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" "$API_METADATA_URL/$ACCESS_LEVEL/$(urlencode "$DIR_DST")?oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM" 2> /dev/null
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then

    local IS_DIR=$(sed -n 's/^\(.*\)\"contents":.\[.*/\1/p' "$RESPONSE_FILE")

    #It's a directory
    if [[ $IS_DIR != "" ]]; then

      print "DONE\n"

      #Extracting directory content [...]
      #and replacing "}, {" with "}\n{"
      #I don't like this piece of code... but seems to be the only way to do this with SED, writing a portable code...
      local DIR_CONTENT=$(sed -n 's/.*: \[{\(.*\)/\1/p' "$RESPONSE_FILE" | sed 's/}, *{/}\
{/g')

      #Converting escaped quotes to unicode format
      echo "$DIR_CONTENT" | sed 's/\\"/\\u0022/' > "$TEMP_FILE"

      #Extracting files and subfolders
      rm -fr "$RESPONSE_FILE"
      while read -r line; do

        local FILE=$(echo "$line" | sed -n 's/.*"path": *"\([^"]*\)".*/\1/p')
        local IS_DIR=$(echo "$line" | sed -n 's/.*"is_dir": *\([^,]*\).*/\1/p')
        local SIZE=$(echo "$line" | sed -n 's/.*"bytes": *\([0-9]*\).*/\1/p')

        echo -e "$FILE:$IS_DIR;$SIZE" >> "$RESPONSE_FILE"

      done < "$TEMP_FILE"

      #Looking for the biggest file size
      #to calculate the padding to use
      local padding=0
      while read -r line; do
        local FILE=${line%:*}
        local META=${line##*:}
        local SIZE=${META#*;}

        if [[ ${#SIZE} -gt $padding ]]; then
          padding=${#SIZE}
        fi
      done < "$RESPONSE_FILE"

      #For each entry, printing directories...
      while read -r line; do

        local FILE=${line%:*}
        local META=${line##*:}
        local TYPE=${META%;*}
        local SIZE=${META#*;}

        #Removing unneeded /
        FILE=${FILE##*/}

        if [[ $TYPE != "false" ]]; then
          FILE=$(echo -e "$FILE")
          $PRINTF " [D] %-${padding}s %s\n" "$SIZE" "$FILE"
        fi

      done < "$RESPONSE_FILE"

      #For each entry, printing files...
      while read -r line; do

        local FILE=${line%:*}
        local META=${line##*:}
        local TYPE=${META%;*}
        local SIZE=${META#*;}

        #Removing unneeded /
        FILE=${FILE##*/}

        if [[ $TYPE == "false" ]]; then
          FILE=$(echo -e "$FILE")
          $PRINTF " [F] %-${padding}s %s\n" "$SIZE" "$FILE"
        fi

      done < "$RESPONSE_FILE"

    #It's a file
    else
      print "FAILED: $DIR_DST is not a directory!\n"
      ERROR_STATUS=1
    fi

  else
    print "FAILED\n"
    ERROR_STATUS=1
  fi
}

#Share remote file
#$1 = Remote file
function db_share
{
  local FILE_DST=$(normalize_path "$1")

  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" "$API_SHARES_URL/$ACCESS_LEVEL/$(urlencode "$FILE_DST")?oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_ACCESS_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_ACCESS_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM&short_url=false" 2> /dev/null
  check_http_response

  #Check
  if grep -q "^HTTP/1.1 200 OK" "$RESPONSE_FILE"; then
    print " > Share link: "
    echo $(sed -n 's/.*"url": "\([^"]*\).*/\1/p' "$RESPONSE_FILE")
  else
    print "FAILED\n"
    ERROR_STATUS=1
  fi
}

################
#### SETUP ####
################

#CHECKING FOR AUTH FILE
if [[ -e $CONFIG_FILE ]]; then

  #Loading data... and change old format config if necesary.
  source "$CONFIG_FILE" 2>/dev/null || {
    sed -i'' 's/:/=/' "$CONFIG_FILE" && source "$CONFIG_FILE" 2>/dev/null
  }

  #Checking the loaded data
  if [[ $APPKEY == "" || $APPSECRET == "" || $OAUTH_ACCESS_TOKEN_SECRET == "" || $OAUTH_ACCESS_TOKEN == "" ]]; then
    echo -ne "Error loading data from $CONFIG_FILE...\n"
    echo -ne "It is recommended to run $0 unlink\n"
    remove_temp_files
    exit 1
  fi

  #Back compatibility with previous Dropbox Uploader versions
  if [[ $ACCESS_LEVEL == "" ]]; then
    ACCESS_LEVEL="dropbox"
  fi

#NEW SETUP...
else

  echo -ne "\n This is the first time you run this script.\n\n"
  echo -ne " 1) Open the following URL in your Browser, and log in using your account: $APP_CREATE_URL\n"
  echo -ne " 2) Click on \"Create App\", then select \"Dropbox API app\"\n"
  echo -ne " 3) Select \"Files and datastores\"\n"
  echo -ne " 4) Now go on with the configuration, choosing the app permissions and access restrictions to your DropBox folder\n"
  echo -ne " 5) Enter the \"App Name\" that you prefer (e.g. MyUploader$RANDOM$RANDOM$RANDOM)\n\n"

  echo -ne " Now, click on the \"Create App\" button.\n\n"

  echo -ne " When your new App is successfully created, please type the\n"
  echo -ne " App Key, App Secret and the Permission type shown in the confirmation page:\n\n"

  #Getting the app key and secret from the user
  while (true); do

    echo -n " # App key: "
    read APPKEY

    echo -n " # App secret: "
    read APPSECRET

    echo -n " # Permission type, App folder or Full Dropbox [a/f]: "
    read ACCESS_LEVEL

    if [[ $ACCESS_LEVEL == "a" ]]; then
      ACCESS_LEVEL="sandbox"
      ACCESS_MSG="App Folder"
    else
      ACCESS_LEVEL="dropbox"
      ACCESS_MSG="Full Dropbox"
    fi

    echo -ne "\n > App key is $APPKEY, App secret is $APPSECRET and Access level is $ACCESS_MSG. Looks ok? [y/n]: "
    read answer
    if [[ $answer == "y" ]]; then
      break;
    fi

  done

  #TOKEN REQUESTS
  echo -ne "\n > Token request... "
  $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --data "oauth_consumer_key=$APPKEY&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM" "$API_REQUEST_TOKEN_URL" 2> /dev/null
  check_http_response
  OAUTH_TOKEN_SECRET=$(sed -n 's/oauth_token_secret=\([a-z A-Z 0-9]*\).*/\1/p' "$RESPONSE_FILE")
  OAUTH_TOKEN=$(sed -n 's/.*oauth_token=\([a-z A-Z 0-9]*\)/\1/p' "$RESPONSE_FILE")

  if [[ $OAUTH_TOKEN != "" && $OAUTH_TOKEN_SECRET != "" ]]; then
    echo -ne "OK\n"
  else
    echo -ne " FAILED\n\n Please, check your App key and secret...\n\n"
    remove_temp_files
    exit 1
  fi

  while (true); do

    #USER AUTH
    echo -ne "\n Please open the following URL in your browser, and allow Dropbox Uploader\n"
    echo -ne " to access your DropBox folder:\n\n --> ${API_USER_AUTH_URL}?oauth_token=$OAUTH_TOKEN\n"
    echo -ne "\nPress enter when done...\n"
    read

    #API_ACCESS_TOKEN_URL
    echo -ne " > Access Token request... "
    $CURL_BIN $CURL_ACCEPT_CERTIFICATES -s --show-error --globoff -i -o "$RESPONSE_FILE" --data "oauth_consumer_key=$APPKEY&oauth_token=$OAUTH_TOKEN&oauth_signature_method=PLAINTEXT&oauth_signature=$APPSECRET%26$OAUTH_TOKEN_SECRET&oauth_timestamp=$(utime)&oauth_nonce=$RANDOM" "$API_ACCESS_TOKEN_URL" 2> /dev/null
    check_http_response
    OAUTH_ACCESS_TOKEN_SECRET=$(sed -n 's/oauth_token_secret=\([a-z A-Z 0-9]*\)&.*/\1/p' "$RESPONSE_FILE")
    OAUTH_ACCESS_TOKEN=$(sed -n 's/.*oauth_token=\([a-z A-Z 0-9]*\)&.*/\1/p' "$RESPONSE_FILE")
    OAUTH_ACCESS_UID=$(sed -n 's/.*uid=\([0-9]*\)/\1/p' "$RESPONSE_FILE")

    if [[ $OAUTH_ACCESS_TOKEN != "" && $OAUTH_ACCESS_TOKEN_SECRET != "" && $OAUTH_ACCESS_UID != "" ]]; then
      echo -ne "OK\n"

      #Saving data in new format, compatible with source command.
      echo "APPKEY=$APPKEY" > "$CONFIG_FILE"
      echo "APPSECRET=$APPSECRET" >> "$CONFIG_FILE"
      echo "ACCESS_LEVEL=$ACCESS_LEVEL" >> "$CONFIG_FILE"
      echo "OAUTH_ACCESS_TOKEN=$OAUTH_ACCESS_TOKEN" >> "$CONFIG_FILE"
      echo "OAUTH_ACCESS_TOKEN_SECRET=$OAUTH_ACCESS_TOKEN_SECRET" >> "$CONFIG_FILE"

      echo -ne "\n Setup completed!\n"
      break
    else
      print " FAILED\n"
      ERROR_STATUS=1
    fi

  done;

  remove_temp_files
  exit $ERROR_STATUS
fi

################
#### START ####
################

COMMAND=${@:$OPTIND:1}
ARG1=${@:$OPTIND+1:1}
ARG2=${@:$OPTIND+2:1}

let argnum=$#-$OPTIND

#CHECKING PARAMS VALUES
case $COMMAND in

  upload)

    if [[ $argnum -lt 2 ]]; then
      usage
    fi

    FILE_DST=${@:$#:1}

    for (( i=$OPTIND+1; i<$#; i++ )); do
      FILE_SRC=${@:$i:1}
      db_upload "$FILE_SRC" "/$FILE_DST"
    done

  ;;

  download)

    if [[ $argnum -lt 1 ]]; then
      usage
    fi

    FILE_SRC=$ARG1
    FILE_DST=$ARG2

    db_download "/$FILE_SRC" "$FILE_DST"

  ;;

  share)

    if [[ $argnum -lt 1 ]]; then
      usage
    fi

    FILE_DST=$ARG1

    db_share "/$FILE_DST"

  ;;

  info)

    db_account_info

  ;;

  delete|remove)

    if [[ $argnum -lt 1 ]]; then
      usage
    fi

    FILE_DST=$ARG1

    db_delete "/$FILE_DST"

  ;;

  move|rename)

    if [[ $argnum -lt 2 ]]; then
      usage
    fi

    FILE_SRC=$ARG1
    FILE_DST=$ARG2

    db_move "/$FILE_SRC" "/$FILE_DST"

  ;;

  copy)

    if [[ $argnum -lt 2 ]]; then
      usage
    fi

    FILE_SRC=$ARG1
    FILE_DST=$ARG2

    db_copy "/$FILE_SRC" "/$FILE_DST"

  ;;

  mkdir)

    if [[ $argnum -lt 1 ]]; then
      usage
    fi

    DIR_DST=$ARG1

    db_mkdir "/$DIR_DST"

  ;;

  list)

    DIR_DST=$ARG1

    #Checking DIR_DST
    if [[ $DIR_DST == "" ]]; then
      DIR_DST="/"
    fi

    db_list "/$DIR_DST"

  ;;

  unlink)

    db_unlink

  ;;

  *)

    if [[ $COMMAND != "" ]]; then
      print "Error: Unknown command: $COMMAND\n\n"
      ERROR_STATUS=1
    fi
    usage

  ;;

esac

remove_temp_files
exit $ERROR_STATUS

For the first time, this script will give you instructions on where to get the Dropbox API key.

Because only the API key is configured to authorize the application of the script into your Dropbox directory