CODEWITHSUNDEEP
bashshellunix
Angelo
Angelo

Reputation: 5069

Sorting data based on second column of a file

I have a file of 2 columns and n number of rows.

column1 contains names and column2 age.

I want to sort the content of this file in ascending order based on the age (in second column).

The result should display the name of the youngest person along with name and then second youngest person and so on...

Any suggestions for a one liner shell or bash script.

Upvotes: 320

Views: 346951

Answers (5)

Logan Lee
Logan Lee

Reputation: 1007

Simply

$ sort -k2,2n <<<"$data"

Upvotes: 0

Matt Ryall
Matt Ryall

Reputation: 10595

You can use the key option of the sort command, which takes a "field number", so if you wanted the second column:

sort -k2 -n yourfile

-n, --numeric-sort compare according to string numerical value

For example:

$ cat ages.txt 
Bob 12
Jane 48
Mark 3
Tashi 54

$ sort -k2 -n ages.txt 
Mark 3
Bob 12
Jane 48
Tashi 54

Upvotes: 480

DCurro
DCurro

Reputation: 1889

Solution:

sort -k 2 -n filename

more verbosely written as:

sort --key 2 --numeric-sort filename

Example:

$ cat filename
A 12
B 48
C 3

$ sort --key 2 --numeric-sort filename 
C 3
A 12
B 48

Explanation:

  • -k # - this argument specifies the first column that will be used to sort. (note that column here is defined as a whitespace delimited field; the argument -k5 will sort starting with the fifth field in each line, not the fifth character in each line)

  • -n - this option specifies a "numeric sort" meaning that column should be interpreted as a row of numbers, instead of text.

More:

Other common options include:

  • -r - this option reverses the sorting order. It can also be written as --reverse.
  • -i - This option ignores non-printable characters. It can also be written as --ignore-nonprinting.
  • -b - This option ignores leading blank spaces, which is handy as white spaces are used to determine the number of rows. It can also be written as --ignore-leading-blanks.
  • -f - This option ignores letter case. "A"=="a". It can also be written as --ignore-case.
  • -t [new separator] - This option makes the preprocessing use a operator other than space. It can also be written as --field-separator.

There are other options, but these are the most common and helpful ones, that I use often.

Upvotes: 120

Saurabh
Saurabh

Reputation: 7833

For tab separated values the code below can be used

sort -t$'\t' -k2 -n

-r can be used for getting data in descending order.
-n for numerical sort
-k, --key=POS1[,POS2] where k is column in file
For descending order below is the code 

sort -t$'\t' -k2 -rn

Upvotes: 23

Ignacio Vazquez-Abrams
Ignacio Vazquez-Abrams

Reputation: 799430

Use sort.

sort ... -k 2,2 ...

Upvotes: 9

Related Questions