My first attempt at a Bash download/install/cache tool. Alpha at best. Didn't need it's own repo.

getdependency.sh

#!/bin/bash

#
# Include source file and line number in xtrace messages
#   From http://wiki.bash-hackers.org/scripting/debuggingtips#making_xtrace_more_useful
#
# export PS4='+(${BASH_SOURCE}:${LINENO}): ${FUNCNAME[0]:+${FUNCNAME[0]}(): }'

#
# Enable xtrace for debugging.
#
# set -x

USAGEMESSAGE="Usage: getdependency [ ... ]\n\
Where options are (* = required):\n\t\
[-c | --cachedir <path>]\t\tWhere to cache the dependency.\n\t\
[-d | --downloadto <path>]\t\tThe directory to git clone or download the dependency to.\n\t\
[-f | --filename <path>]*\t\tThe full local path of the dependency including filename.\n\t\
[-h | --help]\t\t\t\tDisplay this message.\n\t\
[-i | --installdir <path>]\t\tThe directory to unpack/move the dependency to.\n\t\
[-k | --keepdownload]\t\t\tKeep the downloaded file(s) instead of deleting them after caching.\n\t\
[-p | --packedtype <args>]\t\tThe packed type of the dependency, if any; case insensitive.\n\t\t\t\t\t\t\
Options are: TAR, GZ, ZIP, TAR.GZ, and TAR.ZIP.\n\t\
[-q | --quiet]\t\t\t\tShaddap.\n\t\
[-r | --renew]\t\t\t\tGet a new copy of the dependency; ignore the cache.\n\t\
[-s | --source <URL>|<GIT URI>]*\tA URL to download from using 'curl' or a git URI to 'git clone'.\n\t\
[-t | --type URL|GIT]*\t\t\tThe dependency type, either 'URL' or 'GIT', case insensitive."


#
# Default true/false settings..
#

DEPOVERWRITEMODE=false # Do not overwrite.
DEPQUIET=false # Do not run in verbose mode.
DEPKEEPDL=false # Do not keep downloaded files.
DEPRENEW=false # Do not renew cached dependencies.

#echo "Running \"getdependency $@\""

if [[ $# -eq 0 ]]; then
  # display usage..
  echo -e "\t\t**********\tError! -- You need to supply some args!\t**********"
  echo -e "$USAGEMESSAGE"
else
#
# Parse arguments
#
  while [[ $# -gt 0 ]]
  do
    key="$1"
    case $key in
      -c|--cachedir)
        DEPCACHEDIR="$2"
        shift
      ;;
      -d|--downloadto)
        DEPDOWNLOADTO="$2"
        shift
      ;;
      -f|--filename)
        DEPFILENAME="$2"
        shift
      ;;
      -h|--help)
        echo -e "$USAGEMESSAGE"
        exit 0;
      ;;
      -i|--installdir)
        DEPINSTALLDIR="$2"
        shift
      ;;
      -k|--keepdownload)
        DEPKEEPDL=true
      ;;
      -p|--packedtype)
        DEPPACKEDTYPE="$2"
        shift
      ;;
      -q|--quiet)
        DEPQUIET=true
      ;;
      -r|--renew)
        DEPRENEW=true
      ;;
      -s|--source)
        DEPSOURCE="$2"
        shift
      ;;
      -t|--type)
        DEPTYPE="$2"
        if [[ "$DEPQUIET" == true ]]; then
          echo "Before translation: $DEPTYPE"
        fi
        DEPTYPE=$(echo "$DEPTYPE" | tr '[:upper:]' '[:lower:]')
        if [[ "$DEPQUIET" == true ]]; then
          echo "After translation: $DEPTYPE"
        fi
        case $DEPTYPE in
          [Gg][Ii][Tt])
          ;;
          [Uu][Rr][Ll])
          ;;
          *)
            echo -e "\n\nError! Invalid dependency type: $2"
            echo -e "Valid dependency types are 'GIT' and 'URL', case insensitive.\n\n"
            exit 255;
        esac
        shift
      ;;
      *)
        clear
        echo -e "\n\nError! Unknown option: $1\n\n"
        echo -e "$USAGEMESSAGE"
        exit 255;
      ;;
    esac
    shift # To get past the -o/-option.
  done
#
# Validate args and existence of directories; mkdir -p where needed.
#
  if [[ "$DEPCACHEDIR" == "" ]]; then
    echo "If you don't set a cache directory the dependency will be cached in the current directory."
  fi

  if [[ ! -e "$DEPCACHEDIR" ]]; then
    echo "Cache directory doesn't exist. Creating it..."
    mkdir -p $DEPCACHEDIR
  fi

  if [[ "$DEPDOWNLOADTO" == "" ]]; then
    echo "If you don't set a directory to download to the dependency will be downloaded to the current directory."
  fi

  if [[ ! -e "$DEPDOWNLOADTO" ]]; then
    echo "Dep download dir doesn't exist. Creating it..."
    mkdir $DEPDOWNLOADTO
  fi

  if [[ "${DEPFILENAME}" == "" ]]; then
    echo "Error! You must set a dependency file name."
    exit 255;
  fi

  if [[ "$DEPINSTALLDIR" == "" ]]; then
    echo "If you don't set an install directory the dependency will be installed to the current directory."
  fi

  if [[ ! -e "$DEPINSTALLDIR" ]]; then
    echo "Dep install dir doesn't exist. Creating it..."
    mkdir -p $DEPINSTALLDIR
  fi

  if [[ "$DEPKEEPDL" == true ]]; then
    echo -e "**********\tRunning in keepdownload mode. The dependency will not be deleted after caching.\t\t**********"
  fi

  if [[ "$DEPPACKEDTYPE" == "" ]]; then
    echo "If you don't set a packed type it will be assumed that the dependency doesn't need unpacking."
  fi

  if [[ "$DEPQUIET" == true ]]; then
    echo -e "**********\tRunning in quiet mode. This means any prompts will be skipped!\t\t\t\t**********"
  fi

  if [[ "$DEPRENEW" == true ]]; then
    echo -e "**********\tRunning in renew mode. Dependency will be downloaded even if there is a cached copy.\t**********"
  fi

  if [[ "$DEPSOURCE" == "" ]]; then
    echo "You must set a source to get the dependency ${DEPSOURCE}."
    exit 255;
  fi

  if [[ "$DEPTYPE" == "" ]]; then
    echo "Error! You must set a dependency type to get the dependency ${DEPFILENAME}."
    exit 255;
  fi

  if [[ "${DEPQUIET}" == false ]]; then
    STATUS="\n"
    STATUS+="FILE NAME\t=\t${DEPFILENAME}\n"
    STATUS+="PACKED TYPE\t=\t${DEPPACKEDTYPE}\n"
    STATUS+="TYPE\t\t=\t${DEPTYPE}\n"
    STATUS+="SOURCE\t\t=\t${DEPSOURCE}\n"
    STATUS+="DOWNLOAD DIR\t=\t${DEPDOWNLOADTO}\n"
    STATUS+="INSTALL DIR\t=\t${DEPINSTALLDIR}\n"
    STATUS+="CACHE DIR\t=\t${DEPCACHEDIR}\n"
    STATUS+="KEEP DOWNLOAD\t=\t${DEPKEEPDL}\n"
    STATUS+="QUIET MODE\t=\t${DEPQUIET}\n"
    STATUS+="RENEW MODE\t=\t${DEPRENEW}\n\n"
    echo -e "$STATUS"
  fi


fi