Linux Pocket Guide, 2nd Edition

Name

sort — stdin  stdout  - file  -- opt  --help  --version

Synopsis

sort [options] [files]

The sort command prints lines of text in alphabetical order, or sorted by some other rule you specify. All provided files are concatenated, and the result is sorted and printed.

$ cat myfile
def
xyz
abc
$ sort myfile
abc
def
xyz

Useful options

-f	Case-insensitive sorting.
-n	Sort numerically (i.e., 9 comes before 10) instead of alphabetically (10 comes before 9 because it begins with a “1”).
-g	Another numerical sorting method with a different algorithm that, among other things, recognizes scientific notation (7.4e3 means “7.4 times ten to the third power,” or 7400). Run info sort for full technical details.
-u	Unique sort: ignore duplicate lines. (If used with -c for checking sorted files, fail if any consecutive lines are identical.)
-c	Don’t sort, just check if the input is already sorted. If it is, print nothing; otherwise, print an error message.
-b	Ignore leading whitespace in lines.
-r	Reverse the output: sort from greatest to least.
-t X	Use X as the field delimiter for the -k option.
-k key	Choose sorting keys. (Combine with -t to choose a separator character between keys.)

A sorting key is a portion of a line that’s considered when sorting, instead of considering the entire line. An example is “the fifth character of each line.” Normally, sort would consider these lines to be in sorted order:

aaaaz
bbbby

but if your sorting key is “the fifth character of ...