Need help with Math Scripting

[coyboss]

Hi all,

I am trying to figure out how to use a math command to divide one file by another then pipe it to a file.

I have too files one with a value of 10 (lets say file1) and one with a value of 200 (lets say file 2), I need to divide file 2 by file 1 and had results sent to a file (lets say file 3). I am working out of a book and don't quite understand which operations to use or how they are supposed to be combined.


Here is what I have so far:

 #!/bin/bash
var3=`echo "var1=file2; var2=file1; var1 / var2" | bc`
echo output=file3

but I keep getting the following error.

******************************************
[ Ike]$ ./Week3prog3Ike.scr
Runtime error (func=(main), adr=15): Divide by zero
output=file3
**************************************

I have tried it this way too

#!/bin/bash
read File2
read File1
var3=`echo "var1=File2; var2=File1; var1 / var2" | bc | output=File3`
echo

and I am getting this error output:
*****************************
[Ike]$ ./Week3prog3Ike.scr
quit
q
(standard_in) 1: parse error
(standard_in) 1: parse error
******************************

Thanks in advance.

COY

[Pafnoutios]

If the numbers are the contents of files, try using the cat command to get the file contents into stdout.

Remove everything from the ' | bc ...' for now, until you see printed on the screen exactly the text you want being piped into bc.

I don't think bc can be piped into.

Bash has some simple arithmetic abilities inside $[[ ]] brackets.

[lugoteehalt]

echo $(echo "$(cat f1)/$(cat f2)"|bc) > f3

Tried that at the command line and it seemed to work. $(....) is easier to read than backtics. Incidentally I think > is not called a pipe - a 'redirect'?? A pipe is | or a named pipe, a fifo as in mkfifo.

[Pafnoutios]

Incidentally I think > is not called a pipe - a 'redirect'?? A pipe is | or a named pipe, a fifo as in mkfifo.

Yes.