Shell Programming and Scripting

So here is a snippet from an analysis of test runs conducted in a robot experiment in the form of a table:

-----------------------------
| TN | TE | PA | PB |
-----------------------------
| Y | N | - | B |
| N | Y | A | B |

TN = Is the target north?
TE = Is the target east?
PA = Is there a passage ahead?
PB = Is there a passage behind?


How would I go about in writing a BASH script that accepts from the standard input for example:

Code:

echo "| Y | N | - | B |" | ./test

(Straight into the terminal)

And give the output "Target is north, passage behind" for that particular example? This script must take into condition all possible scenarios when conducting the test.

Another example would be:

Code:

 echo "|       N       |     Y     |       A      |      B      |" | ./test

This would output on the standard out "Target is east, passage ahead, passage behind". If anyone can hint me in the right direction then that would be truly appreciated!

something to start with.

Code:

echo '| Y | N | - | B |' | nawk -f ret.awk

ret.awk:

Code:

BEGIN {
  FS="|"

  split("|Target is north|Target is east|Passage is ahead|Passage is behind", whereA, "|")
  howN=split("| Y | Y | A | B ", howA, "|")
}

{
   for(i=2; i <= howN; i++)
     if ( $i == howA[i] )
        printf("%s%s", whereA[i], (i==howN) ? "\n" : ",")
}