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@(#)sort.1 8.1 (Berkeley) 6/6/93
.Dd September 1, 2019 .Dt SORT 1 .Os .Sh NAME .Nm sort .Nd sort or merge text files .Sh SYNOPSIS .Nm .Op Fl bdfHilmnrSsu .Oo .Fl k .Ar kstart Ns Op Li , Ns Ar kend .Oc .Op Fl o Ar output .Op Fl R Ar char .Op Fl T Ar dir .Op Fl t Ar char .Op Ar .Nm .Fl C Ns | Ns Fl c .Op Fl bdfilnru .Oo .Fl k .Ar kstart Ns Op Li , Ns Ar kend .Op Fl t Ar char .Oc .Op Fl R Ar char .Op Ar file .Sh DESCRIPTION The .Nm utility sorts text files by lines. Comparisons are based on one or more sort keys extracted from each line of input, and are performed lexicographically. By default, if keys are not given, .Nm regards each input line as a single field.
p The following options are available: l -tag -width Fl t Fl C Identical to .Fl c without the error messages in the case of unsorted input. t Fl c Check that the single input file is sorted. If the file is not sorted, .Nm produces the appropriate error messages and exits with code 1; otherwise, .Nm returns 0. .Nm .Fl c produces no output. See also .Fl u . t Fl H Ignored for compatibility with earlier versions of .Nm . t Fl m Merge only; the input files are assumed to be pre-sorted. t 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. t Fl S Don't use stable sort. Default is to use stable sort. t Fl s Use stable sort, keeps records with equal keys in their original order. This is the default. Provided for compatibility with other .Nm implementations only. t Fl T Ar dir Use .Ar dir as the directory for temporary files. The default is the value specified in the environment variable .Ev TMPDIR or
a /tmp if .Ev TMPDIR is not defined. t 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
p
The following options,
which should be given before any
.Fl k
options, override the default ordering rules.
When ordering options appear independent of,
and before, 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 ordering options override
all global ordering options for that key.
l -tag -width Fl t Fl d Only blank space and alphanumeric characters
according
to the current setting of LC_CTYPE
are used
in making comparisons.
t Fl f Considers all lowercase characters that have uppercase
equivalents to be the same for purposes of comparison.
t Fl i Ignore all non-printable characters.
t Fl l Sort by the string length of the field, not by the field itself.
t Fl n An initial numeric string, consisting of optional blank space, optional
plus or 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 no longer implies the
.Fl b
option.)
t Fl r Reverse the sense of comparisons.
.El
p The treatment of field separators can be altered using these options: l -tag -width Fl t Fl b Ignores leading blank space when determining the start and end of a restricted sort key. A .Fl b option specified before the first .Fl k option applies globally to all .Fl k options. Otherwise, the .Fl b option can be attached independently to each .Ar field argument of the .Fl k option (see below). Note that the .Fl b option has no effect unless key fields are specified. t Fl k Ar kstart Ns Op Li , Ns Ar kend Designates the starting position, .Ar kstart , and optional ending position, .Ar kend , of a key field. The .Fl k option replaces the obsolescent options .Cm \(pl Ns Ar pos1 and .Fl Ns Ar pos2 . t Fl R Ar char .Ar char is used as the record separator character. This should be used with discretion; .Fl R Aq Ar alphanumeric usually produces undesirable results. If char is not a single character, then it specifies the value of the desired record separator as an integer specified in any of the normal NNN, 0ooo, or 0xXXX ways, or as an octal value preceded by \e. Caution: do not attempt to specify Ctl-A as .Dq -R 1 which will not do what was intended at all! The default record separator is newline. t Fl t Ar char .Ar char is used as the field separator character. The initial .Ar char is not considered to be part of a field when determining key offsets (see below). Each occurrence of .Ar char is significant (for example, .Dq Ar charchar delimits an empty field). If .Fl t is not specified, the default field separator is a sequence of blank-space characters, and consecutive blank spaces do .Em not delimit an empty field; further, the initial blank space .Em is considered part of a field when determining key offsets. .El
p The following operands are available: l -tag -width Ar t Ar file The pathname of a file to be sorted, merged, or checked. If no .Ar file operands are specified, or if a .Ar file operand is .Fl , the standard input is used. .El
p 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 as 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.
p Fields are specified by the .Fl k .Ar kstart Ns Op , Ns Ar kend argument. A missing .Ar kend argument defaults to the end of a line.
p The arguments .Ar kstart and .Ar kend have the form .Ar m Ns Li . Ns Ar n and can be followed by one or more of the letters .Cm b , d , f , i , .Cm l , n , and .Cm r , which correspond to the options discussed above. A .Ar kstart position specified by .Ar m Ns Li . Ns Ar n
q Ar m , n No > 0 is interpreted as the .Ar n Ns th character in the .Ar m Ns th field. A missing .Li . Ns Ar n in .Ar kstart means .Ql .1 , indicating the first character of the .Ar m Ns th field; if the .Fl b option is in effect, .Ar n is counted from the first non-blank character in the .Ar m Ns th field; .Ar m Ns Li .1b refers to the first non-blank character in the .Ar m Ns th field.
p A .Ar kend position specified by .Ar m Ns Li . Ns Ar n is interpreted as the .Ar n Ns th character (including separators) of the .Ar m Ns th field. A missing .Li . Ns Ar n indicates the last character of the .Ar m Ns th field; .Ar m = 0 designates the end of a line. Thus the option .Fl k .Sm off .Xo .Ar v Li . Ar x Li , .Ar w Li . Ar y .Xc .Sm on is synonymous with the obsolescent option .Sm off .Cm \(pl Ar v-1 Li . Ar x-1 .Fl Ar w-1 Li . Ar y ; .Sm on when .Ar y is omitted, .Fl k .Sm off .Ar v Li . Ar x Li , Ar w .Sm on is synonymous with .Sm off .Cm \(pl Ar v-1 Li . Ar x-1 .Fl Ar w+1 Li .0 . .Sm on The obsolescent .Cm \(pl Ns Ar pos1 .Fl Ns Ar pos2 option is still supported, except for .Fl Ns Ar w Ns Li .0b , which has no .Fl k equivalent.
p
.Nm
compares records by comparing the key fields selected by
.Fl k
arguments,
from first given to last,
until discovering a difference.
If there are no
.Fl k
arguments, the whole record is treated as a single key.
After exhausting the
.Fl k
arguments, if no difference has been found,
then the result depends upon the
.Fl u
and
.Fl S
option settings.
With
.Fl u
the records are considered identical, and one is suppressed.
Otherwise with
.Fl s
set (default) the records are left in their original order,
or with
.Fl S
(POSIX mode) the whole record is considered as a tie breaker.
If you fail to understand why it doesn't matter which order
the records are output when they are wholly identical, there
is nothing that this man page can say that wll help!
.Sh ENVIRONMENT
If the following environment variable exists, it is used by
.Nm .
l -tag -width Ev t Ev TMPDIR .Nm
uses the contents of the
.Ev TMPDIR
environment variable as the path in which to store
temporary files.
.El
.Sh FILES
l -tag -width outputNUMBER+some -compact t Pa /tmp/sort.* Default temporary files.
t Ar output Ns NUMBER Temporary file which is used for output if
.Ar output
already exists.
Once sorting is finished, this file replaces
.Ar output
(via
.Xr link 2
and
.Xr unlink 2 ) .
.El
.Sh EXIT STATUS
Sort exits with one of the following values:
l -tag -width flag -compact t 0 Normal behavior.
t 1 On disorder (or non-uniqueness) with the
.Fl c
(or
.Fl C )
option.
t 2 An error occurred.
.El
.Sh SEE ALSO
.Xr comm 1 ,
.Xr join 1 ,
.Xr uniq 1 ,
.Xr qsort 3 ,
.Xr radixsort 3
.Sh HISTORY
A
.Nm
command appeared in
.At v1 .
This
.Nm
implementation appeared in
x 4.4 and is used since
.Nx 1.6 .
.Sh BUGS
POSIX requires the locale's thousands separator be ignored in numbers.
It may be faster to sort very large files in piec
Indexes created Sat Sep 20 22:09:52 GMT 2025