.TH DSORT 1 "June 17, 1986" "\(co 1980 Gary Perlman" "|STAT" "UNIX User's Manual""
.SH NAME
dsort \- multiple key data-file sorting filter
.SH SYNOPSIS
.B dsort
[-aceinr] [-l lines] [[type][column-range]] ...
.SH DESCRIPTION
.I dsort
sorts data it reads from the standard input.
It sorts lines
based on numerical or alphabetical values in whitespace-separated columns.
For when two columns have the same value,
you can supply further sorting columns to break ties.
.I dsort
sorts by looking at columns you choose,
and orders lines so that the data or labels in the chosen columns
are ordered.
You can name the specific column numbers you want,
and you can use the M-N notation to specify
a sequence, from M to N, of columns.
Ranges can be from small to large or from large to small column numbers.
If you don't supply columns to sort with,
.I dsort
uses column 1, then 2, then 3, and so on,
until it finds a difference, or all columns are used.
.PP
You can supply the method for comparing column values:
.B a,
for alphabetical,
.B i,
for integer,
.B n,
for most other numbers, including those with decimal points,
or
.B e,
for sorting all types of numbers,
even ones with exponential scientific notation.
If you do not supply the type of sort,
.I dsort
chooses the one that is best suited for the data,
although this makes
.I dsort
do some extra work.
For alphabetical sorts,
you can request a case-insensitive sort with
.B c;
that would make
.I hello
match
.I Hello
and
.I HELLO.
You can reverse the sort from the default ascending order to descending order
with
.B r.
These sorting types can be specified globally for all columns at once
with command line options.
Global types can
be over-ridden by supplying options for specific
columns or ranges of columns.
.SH OPTIONS
.de OP
.TP
.B -\\$1 \\$2
..
.OP a
Sort fields by alphabetic ordering of columns.
.OP c
Use a case-insensitive comparison for alphabetic comparisons.
When used as a type modifier for a specific range of columns,
this also forces alphabetic sorting.
As a command line option,
it only modifies the sorting of alphabetic columns.
.OP e
Sort fields by exponential notation ordering of columns.
This is the only true numeric sort that works for all numbers:
integers, numbers with decimal points, and exponential (scientific) notation
numbers.
But it is a lot slower than the other sorting options,
especially on machines without floating point hardware.
.OP i
Sort fields by integer ordering of columns.
.OP l lines
Set the maximum number of lines to be read.
.OP n
Sort fields by special numeric ordering of columns.
Numbers with decimal points are allowed,
and compared by a special fast comparison method
that is almost as fast as integer sorting.
.OP r
Reverse the order of comparison for sorting options.
.SH EXAMPLES
.ta 1i 2i 3i 4i 5i 6i
.de (D
.br
.if t .ft B
.if n .ft I
.nf
.if t .sp 6p
.if n .sp
.ne 1i
.if \\n(.$ \\$1   \fR# \\$2
.if t .ps 9p
.if t .vs 10p
.ft R
..
.de )D
.if t .ps
.if t .vs
.fi
..
Suppose the file
.I ex.dat
has the contents below.
If you did not specify column types,
.I dsort
would infer that columns 1 and 2 were to be sorted alphabetically,
column 3, as integers,
and column 4, numerically.
.(D "ex.dat" "file with four columns (alpha, alpha, integer, numerical)
red	high	1	3.14
blue	low	2	1.62
green	high	6	2.54
green	low	4	2.71
blue	high	3	1
red	low	5	1
.)D
.(D "dsort  <  ex.dat" "sort by column 1, then 2, then 3, then 4
blue	high	3	1
blue	low	2	1.62
green	high	6	2.54
green	low	4	2.71
red	high	1	3.14
red	low	5	1
.)D
.(D "dsort  i3  <  ex.dat" "sort column 3 in ascending order
red	high	1	3.14
blue	low	2	1.62
blue	high	3	1
green	low	4	2.71
red	low	5	1
green	high	6	2.54
.)D
.(D "dsort  rn4  3  <  ex.dat" "numerically sort column 4 in reverse order, then 3
red	high	1	3.14
green	low	4	2.71
green	high	6	2.54
blue	low	2	1.62
blue	high	3	1
red	low	5	1
.)D
.(D "dsort  rn4  r3  <  ex.dat" "reverse numerical sort of column 4 and then 3
red	high	1	3.14
green	low	4	2.71
green	high	6	2.54
blue	low	2	1.62
red	low	5	1
blue	high	3	1
.)D
.(D "dsort  2-1  <  ex.dat" "sort by column 2, then column 1 within ties in 2
blue	high	3	1
green	high	6	2.54
red	high	1	3.14
blue	low	2	1.62
green	low	4	2.71
red	low	5	1
.)D
.SH LIMITS
Use the -L option to determine the program limits.