SyntaxFix

[bash] Sorting data based on second column of a file

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.

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