UNIX for Dummies Questions & Answers

I am trying to write a program in a script .sh

I have a list of coordinates ie
e1=123 n1=123
e2=456 n2=456
e3=789 n3=789

I have a counter starting at 1
for (( i=1; i<=2; i++))
i need coordinate=123,123
then on the second loop
coordinate=456,456 etc...

I tried doing:

Code:

#e=0 n=0 < just to show what e and n return
#Coordinates
e1=123 n1=123
e2=456 n2=456

coordinate = $e$i,$n$i

this will not work it returns 01,02

i need it to think coordinate=$e$i = $e1 = 123
and coordinate=$n$i = $n1 = 123

can any one help?

Thanks

Gary

Hi gazz1982,

I dont think using a variable name like that should work.

take a look at arrays:
http://tldp.org/LDP/abs/html/arrays.html

or a more ugly hack:
e="123,456,789"

echo $e | cut -d , -f $counter

Place all your coordinates separated by space into a file:

Code:

123 123
456 456
789 789

Write a shell as following:

Code:

while read mX mY
do
  echo 'X = '${mX}' Y = '${mY}
done < CoordFile

hi
i think you want
eval coordinates=\$e$i,\$n$i

without eval
coordinates=\$e$i,\$n$i
evaluates (for i=1) to
coordinates=$e1,$e2
(you can check this by calling
echo coordinates=\$e$i,\$n$i
eval gives an extra evaluation, that is, it evaluates
coordinates=$e1,$e2

mfg guenter