Traslating .eml file to a maildir filename.

eml2maildir.sh

#!/bin/bash
# Copyright (C) 2013 Emanuele Tomasi <targzeta@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 3 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, see <http://www.gnu.org/licenses/>.

# Traslates .eml file to maildir format.

# -h help

SCRIPT_NAME=${0##*/}
SCRIPT_AUTHOR="Emanuele Tomasi <targzeta@gmail.com>"


#############
# FUNCTIONS #
#############
function _exit
{
  echo -e "${SCRIPT_NAME}: ${1}"
  exit $2
}

function _help
{
  cat <<EOF
Use: ${SCRIPT_NAME} [option]... file destdir

Translates a .eml file to a maildir filename. For setting hostname it uses
HOST environment variable or, if it isn't setted, HOSTNAME.
The default filename is for new/ directory.

Options:
    -c    Setting the filename for a cur/ directory. You can set your flag by
          setting the FLAG environment variable. Default FLAG is 'S'.
    -d    Dovecot extension. Sets the 'W' option.
    -h    Display this help and exit.

by ${SCRIPT_AUTHOR}"
EOF
}

function _check_extern_programs
{
  local error=0
  local string_error

  if ! which --version >&/dev/null
  then
    error=1
    string_error="which : command not founds.\n";
  else
    for progr in $@
    do

      if ! which $progr >& /dev/null
      then
        error=1
        string_error=${string_error}"${progr} : command not founds.\n"
      fi
    done
  fi

  if (( $error ))
  then
    _exit "You need to install these commands:\n$string_error" 1
  fi
}


##########
# CHECKS #
##########
enable getopts echo exit

IFS=$'\n\t '

OPT_C=0
OPT_D=0
while getopts :hcd opzione
do
  case $opzione in
    c) OPT_C=1;;
    d) OPT_D=1;;
    h) _help; exit;;
    ?) _exit "-${OPTARG} : not valid argument." 1;;
  esac
done

while (( $OPTIND != 1 ))
do
  shift
  let --OPTIND
done

[ -z "$1" -o -z "$2" ] &&  _exit "missing argument. "\
"${SCRIPT_NAME} -h for help." 1

_check_extern_programs date fromdos head mktemp stat touch


########
# MAIN #
########
file=$1
destdir=$2

_TMPFILE=$(mktemp)

[ -z ${_TMPFILE} ] && exit 1

fromdos < $file > $_TMPFILE

_HOST=${HOST:-$HOSTNAME}
_RANDOM=$(</dev/urandom tr -cd '[:digit:]' | head -c 6)
_DATE=$(sed -n '/^Date:/{s/Date: //;p;q}' $file)
_TIMESTAMP=$(date --date="$_DATE" '+%s')
_SIZE=$(stat $_TMPFILE --printf='%s')

_FILENAME="${_TIMESTAMP}.P${_RANDOM}Q2.${_HOST},S=${_SIZE}"

if (( $OPT_D == 1 ))
then
  _WSIZE=$(stat $file --printf='%s')
  _FILENAME+=",W=${_WSIZE}"
fi

if (( $OPT_C == 1 ))
then
  _FLAG=${FLAG:-S}
  _FILENAME+=":2,${_FLAG}"
fi

_OUTPUT_FILE=${destdir}/${_FILENAME}
mv $_TMPFILE $_OUTPUT_FILE
touch --date="${_DATE}" $_OUTPUT_FILE

This fails pretty badly for files with spaces.
I'd recommend quoting all file and folder paths.

(and it said it could not find which - which was obviously wrong on my fresh Debian 8)