These docs are under active development and cover the v0.20 Kobicha security model.
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sort

sort reads lines and writes them out in order.

sort [options] [file...]

$ sort names.txt

With no file, sort reads standard input. Given several files, it sorts all of their lines together as one stream. By default it compares lines as plain text, character by character.

How lines are compared

The default text comparison is often not the order you want — 10 sorts before 9, and case matters. These options change the comparison:

Option Compares lines as…
-n, --numeric-sort numbers. 9 sorts before 10.
-g, --general-numeric-sort numbers, including scientific notation. Slower than -n; use it only when -n is not enough.
-h, --human-numeric-sort human-readable sizes — 2K before 1M before 3G.
-M, --month-sort month names — JAN before FEB.
-V, --version-sort version numbers — 1.2.10 after 1.2.9.
-R, --random-sort a random order (a shuffle that groups equal lines together).

And these adjust what is compared:

Option Effect
-f, --ignore-case Treat lower and upper case as the same.
-d, --dictionary-order Consider only letters, digits, and blanks.
-i, --ignore-nonprinting Ignore non-printing characters.
-b, --ignore-leading-blanks Ignore blanks at the start of a line (or field).

Sort order options

Option Effect
-r, --reverse Reverse the result.
-u, --unique Output only the first line of each run of equal lines — sort and de-duplicate in one step.
-s, --stable Keep equal lines in their original relative order.

Sorting by a field

By default sort compares whole lines. -k sorts on a key — a chosen part of each line — which is what you need for tabular data.

A line is split into fields (by default at whitespace). A key is written FIELD[.CHAR][OPTIONS][,FIELD[.CHAR]] — a start field, an optional start character within it, and an optional end. The single-letter comparison options above can be appended to a key to apply only to it.

$ sort -k 2 -n scores.txt        # sort on the 2nd field, numerically
$ sort -t , -k 3 people.csv      # sort a CSV on the 3rd field
Option Effect
-k, --key=KEYDEF Sort on the key KEYDEF. May be given more than once; keys are tried in order.
-t, --field-separator=SEP Use SEP to split fields, instead of the whitespace default.

Checking and merging

Option Effect
-c, --check Do not sort — just check whether the input is already sorted, and report the first line that is out of order.
-C, --check=silent Check, but report only through the exit status.
-m, --merge Treat the inputs as already-sorted files and merge them, which is faster than a full sort.

Output and resources

Option Effect
-o, --output=FILE Write to FILE instead of standard output. FILE may be one of the inputs.
-z, --zero-terminated Treat the NUL character as the line delimiter.
--parallel=N Use N threads.
-S, --buffer-size=SIZE Set the size of the in-memory sort buffer.
-T, --temporary-directory=DIR Put temporary files in DIR rather than the default location.
--files0-from=F Take the list of input files from F, NUL-separated.
--debug Underline the part of each line that was actually used as the sort key — invaluable when a -k key is not behaving.

Exit status

Code Meaning
0 The lines were sorted — or, with -c/-C, the input was already sorted.
1 With -c/-C, the input was not sorted.
2 An error — a file could not be read, or an option was invalid.

See also