Как я могу получить доступ к старым электронным письмам KMail после обновления до Ubuntu 11.10?

Используйте этот сценарий оболочки для преобразования mdir к mbox формату

#! /bin/sh
#
# Get a directory name as input and convert all mail files inside
# to mbox format
#
# NOTE: processing of subdirectories not yet implemented correctly:
#       all mails in subfolders are put into the same mbox
#       (it would be better if an mbox file will be generated for
#       each subfolder)
#
# History:
# Feb 06 2001 Joerg Reinhardt
# - first edition
# Feb 07 2001 Joerg Reinhardt
# - added usage output
# Feb 12 2001 Joerg Reinhardt
# - mails not containing a 'From:' field but an 'X-From-Line:' or a
#   'Reply-To:' field are now recognised and also processed (e.g. put into
#   the mbox file); this works fine for all my mails
# - added progress information
# - warning about corrupt files is now written to stderr
# Sep 8 2012 Kim Johansson
# - Time conversion to local timezone added
# - changed grep "Date:" to grep "Date: "

# check for argument or help argument respectively
if [[ ($1 == "") ||
($1 == "-h") ||
($1 == "--help") ||
($1 == "-help") ]]; then
echo "Usage: "$0" <Xfmail-mail-directory>";
fi;

# check if parameter is a directory
if [[ -d $1 ]]; then
# set target filename
dirname=`echo $1 | awk '{while(substr($0,length($0),1)=="/"){$0=substr($0,1,length($0)-1);}print $0;}'`;
mboxfile=$dirname'.mbox';

# check if directory is empty
if [[ `find $dirname -type f` == "" ]]; then
        echo $dirname": directory empty."
        exit 1;
fi;

# prevent automatic overwriting of target
if [[ -e $mboxfile ]]; then \
        dialogtext="Write file "$mboxfile"?";
        if dialog --yesno "$dialogtext" 10 60; then
        clear;
        rm -vf $mboxfile;
        else
        clear; exit 1;
        fi;
fi;

echo "writing xfmail mail directory '$1' to '$mboxfile'.";

# so we can handle filnames with space
IFS=$(echo -en "\n\b")
# collect files inside Xfmail mail-directory and produce MBOX format
# target file
#    for i in `find $1/* -type f -ls | cut -b 69-`; do
for i in `find $1/* -type f`; do
# output progress information
        echo -n -e \\r"                                                                               "
        echo -n -e \\rprocessing $i
# look for senders email address in the order
# 'From:'
# 'X-From-Line:'
# 'Reply-To:'
        shortfromflag='true';
        fromline=`grep 'From:' $i`;
# parse 'From:' field
        from=`echo $fromline | awk 'BEGIN{FS="<";}{if($0~/</) {pos=index($2,">");if(pos!=0) {print substr($2,1,pos-1);}} else {pos=index($0,":");print substr($0,pos+1);}}'`;
        if [[ $from == "" ]]; then
        shortfromflag='false';
        fromline=`grep 'X-From-Line:' $i`;
        from=`echo $fromline | awk 'BEGIN{FS="Line:";}{print $2;}'`;
        if [[ $from == "" ]]; then
                shortfromflag='true';
                fromline=`grep 'Reply-To:' $i`;
# parse 'Reply-To:' field
                from=`echo $fromline | awk 'BEGIN{FS="<";}{if($0~/</) {pos=index($2,">");if(pos!=0) {print substr($2,1,pos-1);}} else {pos=index($0,":");print substr($0,pos+1);}}'`;
                if [[ $from == "" ]]; then
                echo;
                echo "WARNING: "$i": no 'From:' nor 'X-From-Line:' nor 'Reply-To:' field found." >&2;
                continue;
                fi;
        fi;
        fi;
        if [[ $shortfromflag == "true" ]]; then
# parse date field
        dateline=`grep 'Date: ' $i`;
        if [[ $dateline == "" ]]; then
# set dummy date if no date field found
                dateline="Date: Thu, 01 Jan 1970 00:00:00 +0000 (GMT)";
        fi;
        datel=`echo $dateline | cut -b7- -`
# Convert to local time
        dateli=`date --date="$datel"`

# output MBOX mail header
        echo "From " $from $dateli >> $mboxfile;
        else
# output long MBOX mail header found in 'X-From-Line:' field
        echo $from >> $mboxfile;
        fi;

# output mail itself
        cat $i >> $mboxfile;
done;
echo;
else
echo $1": not a directory.";
fi;

Если Ваша почта находится в формат mbox , это легко

cd ~/.kde/share/apps/kmail/mail/
cat file1 file2 file3 ...  >>/var/spool/mail/$USER 

file1 file2 file3..., Ваши почтовые папки в mbox формате (не копируйте .index .index.ids .index.sorted файлы)

Теперь можно получить почту от любого почтового клиента путем выбора локальной доставки

, я использую тандерберд:
тип Сервера: сервер Unix Movemail
: localhost
Это было сделано в Slackware, который использует sendmail в качестве MDA, таким образом Ваш dir шпульки может быть отличающийся .