mjhjmtu

I have list of numbers like this:

0987656787689
2345453326780
3453212332345
1324532449876
1234532444568
3245321343456
1324354532376
1234532153457

I would like to sort the numbers based on the results of multiplication of digits in positions sixth and seventh, so the results are like this:

3245321343456
3453212332345
1234532153457
1234532444568
1324532449876
2345453326780
1324354532376
0987656787689

Using awk:

$ awk ' print substr($0,6,1)*substr($0,7,1) ' <file
30
15
2
6
6
2
20
6

Sorting the original numbers based on the the above result (this was a followup question in a comment):

$ awk ' print substr($0,6,1)*substr($0,7,1) ' <file | paste - file | sort -n | cut -f 2
3245321343456
3453212332345
1234532153457
1234532444568
1324532449876
2345453326780
1324354532376
0987656787689

This pastes the result of the multiplication together with the original numbers as two separate tab-delimited columns, then sorts it numerically and extracts the second column (the original numbers).

Perl to the rescue!

perl -F// -lane 'print $F[5] * $F[6]' < file

• 
  -n reads the input line by line


• 
  -a splits each line into the @F array


• 
  -F tells how to split


• 
  // means to split everywhere, i.e. into single characters


• 
  -l removes newlines from input and adds them to output