Этот скрипт должен выполнить трюк:
BEGIN{
FS=";"
OFS=";"
month["Jan"] = "01"
month["Feb"] = "02"
month["Mar"] = "03"
month["Apr"] = "04"
month["May"] = "05"
month["Jun"] = "06"
month["Jul"] = "07"
month["Aug"] = "08"
month["Sep"] = "09"
month["Oct"] = "10"
month["Nov"] = "11"
month["Dec"] = "12"
}
{
split($4,date," ")
$4 = date[3]"-"gsub(",","",date[2])"-"month[date[1]]
print
}
вызов с awk -f script.awk youinput.txt