Sorting data based on second column of a file

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

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.