simple script rotating table

Question

I'm trying to write a simple script, that just rotates csv table. I mean I have some file:

head1;head2;head3
field11;field12;field13

and so on. All I want, just to make my file

head1;field11;field21
head2;fielad12;field22
head3;field13;field23

I even haven't any idea about how it may work. I don't ask you to write a script, I need idea about how I can maje it in standart shell (unfortunately I'm not able to use bashism or gnu extensions, POSIX only)

ps. Actually I can do it, but only in ugly way with unbelievable enefficient multirereading file with table. I believe there is more beautiful way.

Answer 1

Here's a quick adaptation of the bash solution to this similar SO question for the particular separators you have (semicolons):

declare -a array=( )                      # we build a 1-D-array

IFS=';' read -a line < "$1"                       # read the headline

COLS=${#line[@]}                          # save number of columns

index=0
while IFS=';' read -a line ; do
    for (( COUNTER=0; COUNTER<${#line[@]}; COUNTER++ )); do
        array[$index]=${line[$COUNTER]}
        ((index++))
    done
done < "$1"

for (( ROW = 0; ROW < COLS; ROW++ )); do
  printf "%s" ${array[$ROW]}
  for (( COUNTER = ROW+COLS; COUNTER < ${#array[@]}; COUNTER += COLS )); do
    printf ";%s" ${array[$COUNTER]}
  done
  printf "\n" 
done

Answer 2

flds=3; for((i=1;i<=flds;i++));do
  printf '%s' "$(cut -d';' -f$i file)" |tr '\n' ';';echo
done