How to sort and get unique values from an array in bash?

Question

Im new to bash scripting... Im trying to sort and store unique values from an array into another array. eg:

list=('a','b','b','b','c','c');

I need,

unique_sorted_list=('b','c','a')

I tried a couple of things, didnt help me ..

sorted_ids=($(for v in "${ids[@]}"; do echo "$v";done| sort| uniq| xargs))

or

sorted_ids=$(echo "${ids[@]}" | tr ' ' '\n' | sort -u | tr '\n' ' ')

Can you guys please help me in this ....

@kevin . I understood now ...everythings fine...it sorts as (a b c) but I need (b c a) since it has b is three times c 2times and a once.. That is the question i intended to ask — Karthik
– Karthik, Commented Feb 14, 2015 at 6:26

jaypal singh · Accepted Answer · 2015-02-14 06:25:55Z

2

Try:

$ list=(a b b b c c)
$ unique_sorted_list=($(printf "%s\n" "${list[@]}" | sort -u))
$ echo "${unique_sorted_list[@]}"
a b c

Update based on comments:

$ uniq=($(printf "%s\n" "${list[@]}" | sort | uniq -c | sort -rnk1 | awk '{ print $2 }'))

edited Feb 14, 2015 at 6:25

answered Feb 14, 2015 at 5:28

jaypal singh

77.6k24 gold badges108 silver badges147 bronze badges

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

7 Comments

Karthik Over a year ago

Hi Jaypal , your case works, But :-( in my case it is ('a','a','a','b','b','b') not (a a a b b b b b) ....Because of the quotes it takes each value to be unique and prints the same array ...I guess

Karthik Over a year ago

actually my array contains user names of files...This is how I get it

Karthik Over a year ago

for file in $fList; do dList+="$(ls -lt $file | awk '{ print $3 }')" done ------- from dList I need to get sorted , unique array

jaypal singh Over a year ago

@Karthik In bash the array elements are separated by a space.

Karthik Over a year ago

@jayapal..thanks I understand this.. but when I do the command "for file in $flist.." given in my previous comment and when I do echo $dList it prints the names without any space ...thats the problem..

|

mivk · Accepted Answer · 2022-01-03 12:38:46Z

1

The accepted answer doesn't work if array elements contain spaces.

Try this instead:

readarray -t unique_sorted_list < <( printf "%s\n" "${list[@]}" | sort -u )

In Bash, readarray is an alias to the built-in mapfile command. See help mapfile for details.

The -t option is to remove the trailing newline (used in printf) from each line read.

answered Jan 3, 2022 at 12:38

mivk

15.4k5 gold badges89 silver badges83 bronze badges

Collectives™ on Stack Overflow

How to sort and get unique values from an array in bash?

2 Answers 2

Update based on comments:

7 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Update based on comments:

7 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related