Bash - sorting by substring of elements

Question

I would like to sort the elements in a list by the second and third char of the elements in reverse , i.e sort by the 3rd char first and then 2nd char.

eg. If there's an array like this

array=(XA11000 XB21000 XA31000 XB12000)

The desired output of the sort would be (XA31000 XB21000 XB12000 XA11000)

It's relatively simple without the 4 digits at the end of each elements as

echo "${array[@]}"|rev | sort -r | rev

would work.

However I'm not too sure how this would work with the numbers at the end. Any suggestions?

I may just be slow, but it is entirely unclear the sort order you want? sort ... by the second and third char of the elements in reverse , i.e sort by the 3rd char first and then 2nd char. Does this mean the second and third char after reverse ignoring leading 000? ...and.. your explanation of ` 3rd char first and then 2nd char` would apply without reversing? — David C. Rankin
– David C. Rankin, Commented Sep 7, 2015 at 20:43
sorry should've been more clear. What I meant was I would like to pipe the result of sorting the 3rd character in descending order first, then pipe the result and sort by the second character in descending order. — Zocr
– Zocr, Commented Sep 7, 2015 at 22:15

choroba · Accepted Answer · 2018-01-09 08:14:33Z

12

sort has the option -k where you can specify how to sort:

(   IFS=$'\n'
    echo "${array[*]}" | sort -k1.3,1.3r -k1.2,1.2r
)

i.e. sort by the substring from the first word third character (-k1.3) to first word third character (,1.3) reversed r, secondary sorting by the first word second character.

edited Jan 9, 2018 at 8:14

answered Sep 7, 2015 at 20:44

choroba

245k27 gold badges221 silver badges304 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

l'L'l Over a year ago

Dumb question, what do the parentheses do? Just curious. Nice answer +1

Reinstate Monica Please Over a year ago

create a subshell, so the IFS change isn't propagated outside of it

choroba Over a year ago

@l'L'l: The whole thing runs in a subshell to localize the change in IFS (which separates the array members by newlines).

l'L'l Over a year ago

@choroba: Thanks — makes perfect sense now. (good hint BroSlow) :)

Zocr Over a year ago

This site ss64.com/bash/sort.html provides examples of sorting with use of -k argument. I found it useful.

|

Collectives™ on Stack Overflow

Bash - sorting by substring of elements

1 Answer 1

6 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Related