Bash sorting comma delimited columns numerically and then alphabetically

Question

I'm trying to sort 3 columns numerically in reverse (descending) by the third column first and then sort by the first column alphabetically (to break ties). Entries are delimited by commas( , ).

For example, my dataset is:

y,5,50
x,10,50
z,4,100

Expected output:

z,4,100
x,10,50
y,5,50

However the output I am getting is:

z,4,100
y,5,50
x,10,50

I am using:

sort -t, -k3,3 -n -r -k1,1 filename

Not sure why this is not working.

Answer 1

I suggest to replace -k3,3 -n -r by -k3,3nr :

sort -t, -k3,3nr -k1,1 file

Output:

z,4,100
x,10,50
y,5,50

Answer 2

The reason what you're suggesting doesn't work is becuase you've applied the flags -n , -r globally hence the alphabetical sorting is also -r eversed. To apply the flag on a per key basis, use:

sort -t, -k3,3nr -k1,1 filename

This gives the expected output:

z,4,100  
x,10,50  
y,5,50