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.\" the Institute of Electrical and Electronics Engineers, Inc.
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.\"     @(#)sort.1	8.2 (Berkeley) 5/4/95
.\"
.Dd May 4, 1995
.Dt SORT 1
.Os
.Sh NAME
.Nm sort
.Nd sort or merge text files
.Sh SYNOPSIS
.Nm sort
.Op Fl mubdfinrtx
.Oo
.Cm \(pl Ns Ar pos1
.Op Fl Ns Ar pos2
.Oc
.Ar ...
.Op Fl o Ar output
.Op Fl T Ar directory
.Op Ar file
.Ar ...
.Sh DESCRIPTION
The
.Nm sort
utility
sorts text files by lines.
Comparisons are based on one or more sort keys (or fields) extracted
from each line of input, and are performed
lexicographically. By default, if keys are not given,
.Nm sort
regards each input line as a single field.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl c
Check that the single input file is sorted lexicographically.
If the file is not sorted,
.Nm sort
sorts it and writes the sorted output to the standard output or the
filename specified by the
.Fl o
option.
.It Fl m
Merge only; the input files are assumed to be pre-sorted.
.It Fl o Ar output
The argument given is the name of an
.Ar output
file to
be used instead of the standard output.
This file
can be the same as one of the input files.
.It Fl T Ar directory
The argument
.Ar directory
is used for creating temporary files.
.It Fl u
Unique: suppress all but one in each set of lines
having equal keys.
If used with the
.Fl c
option,
check that there are no lines with duplicate keys.
.El
.Pp
The following options override the default ordering rules.
When ordering options appear independent of key field
specifications, the requested field ordering rules are
applied globally to all sort keys.
.\" When attached to a
.\" specific key
.\" (see
.\" .Fl k ) ,
.\" the specified ordering options override
.\" all global ordering options for that key.
.Bl -tag -width indent
.It Fl d
Only blank space and alphanumeric characters
.\" according
.\" to the current setting of LC_CTYPE
are used
in making comparisons.
.It Fl f
Considers all lowercase characters that have uppercase
equivalents to be the same for purposes of
comparison.
.It Fl i
Ignore all non-printable characters.
.It Fl n
An initial numeric string, consisting of optional
blank space, optional minus sign, and zero or more
digits (including decimal point)
.\" with
.\" optional radix character and thousands
.\" separator
.\" (as defined in the current locale),
is sorted by arithmetic value.
The
.Fl n
option implies
the
.Fl b
option. (See below.)
Note that the
.Fl b
option
is only effective when key fields have been specified
and that
.Fl \&0
is considered equal to zero.
.It Fl r
Reverse the sense of comparisons.
.El
.Pp
The treatment of field separators can be altered using the
options:
.Bl -tag -width indent
.It Fl b
Leading blank spaces are ignored when determining the starting
ending positions of a restricted sort key.
If the
.Fl b
option is specified before the first
.Cm \(pl Ns Ar pos1
argument, it shall be applied to all
.Cm \(pl Ns Ar pos1
arguments.
Otherwise, the
.Fl b
option can be
attached independently to each
.Cm \(pl Ns Ar pos1
or
.Fl Ar pos2
argument (see below).
.It Fl t Ar char
.Ar Char
is used as the field separator character;
.Ar char
is not considered to be part of a field (although it
can be included in a sort key).
Each occurrence of
.Ar char
is significant (for example,
.Dq Ar charchar
delimits an empty field).
If
.Fl t
is not specified,
blank space characters are used as default field
separators.
.It Cm \(pl Ns Ar pos1
Designates the start position of a key field.
.It Fl Ns Ar pos1
Designates the end position of a key field.
.El
.Pp
The following operands are available:
.Bl -tag -width indent
.Ar file
The pathname of a file to be sorted, merged, or checked.
If no file
operands are specified, or if
a file operand is
.Fl ,
the standard input is used.
.Pp
A field is
defined as a minimal sequence of characters followed by a
field separator or a newline character.
By default, the first
blank space of a sequence of blank spaces acts as the field separator.
All blank spaces in a sequence of blank spaces are considered
to be part of the next field; for example, all blank spaces at
the beginning of a line are considered to be part of the
first field.
.Pp
Fields are specified
by the
.Cm \(pl Ns Ar pos1
and
.Fl Ar pos2
arguments.  A missing
.Cm \(pl Ns Ar pos1
argument defaults to the beginning of a line.
A missing
.Fl Ar pos2
argument defaults to the end of a line.
.Pp
The arguments
.Cm \(pl Ns Ar pos1
and
.Fl Ar pos2
have the form
.Em m.n
followed by one or more of the options
.Fl b , d , f , i ,
.Fl n , r .
A
.Cm \(pl Ns Ar pos1
position specified by
.Em m.n
is interpreted to
mean the
.Em n Ns th
character in the
.Em m Ns \(pl1th
field.
A missing
.Em \&.n
means
.Ql \&.0 ,
indicating the first character of the
.Em m Ns \(pl1th
field.
If the
.Fl b
option is in effect,
.Em n
is counted from the first
non-blank character in the
.Em m Ns \(pl1th
field;
.Em m Ns \&.0b
refers to the first
non-blank character in the
.Em m Ns \(pl1th
field.
.Pp
A
.Fl Ar pos2
position specified by
.Em m.n
is interpreted to mean
the
.Em n Ns th
character (including separators) after the last
character of the
.Em m Ns th
field.
A missing
.Em \&.n
means
.Ql \&.0 ,
indicating
the last character of the
.Em m Ns th
field.
If the
.Fl b
option
is in effect,
.Em n
is counted from the last leading blank character in
the
.Em m Ns \(pl1th
field;
.Em m Ns \&.1b
refers to the first non-blank character in the
.Em m Ns \(pl1th
field.
.Sh FILES
.Bl -tag -width Pa -compact
.It Pa /var/tmp/stm*, /tmp/*
Default temporary directories (in order of search).
.El
.Sh SEE ALSO
.Xr comm 1 ,
.Xr uniq 1 ,
.Xr join 1
.Sh DIAGNOSTICS
.Sh BUGS
Lines which are longer than 4096 are discarded and processing continues.
.Sh HISTORY
A
.Nm
command appeared in
.At v6 .