sort(1)
NAME
sort - sort, merge, or sequence check text files
SYNOPSIS
/usr/bin/sort [-bcdfimMnru] [-k keydef] [-o output] [-
S kmem] [-t char] [-T directory] [ -y [kmem]] [-z recsz] [
+pos1 [-pos2]] [file...]
/usr/xpg4/bin/sort [-bcdfimMnru] [-k keydef] [-o output] [-
S kmem] [-t char] [-T directory] [ -y [kmem]] [-z recsz] [
+pos1 [-pos2]] [file...]
DESCRIPTION
The sort command sorts lines of all the named files together
and writes the result on the standard output.
Comparisons are based on one or more sort keys extracted
from each line of input. By default, there is one sort key,
the entire input line. Lines are ordered according to the
collating sequence of the current locale.
OPTIONS
The following options alter the default behavior:
/usr/bin/sort
-c Checks that the single input file is ordered as speci-
fied by the arguments and the collating sequence of
the current locale. The exit code is set and no output
is produced unless the file is out of sort.
/usr/xpg4/bin/sort
-c Same as /usr/bin/sort except no output is produced
under any circumstances.
-m Merges only. The input files are assumed to be already
sorted.
-o output
Specifies the name of an output file to be used
instead of the standard output. This file can be the
same as one of the input files.
-S kmem
Specifies the maximum amount of swap-based memory used
for sorting, in kilobytes (the default unit). kmem can
also be specified directly as a number of bytes (b),
kilobytes (k), megabytes (m), gigabytes (g), or tera-
bytes (t); or as a percentage (%) of the installed
physical memory.
-T directory
Specifies the directory in which to place temporary
files.
-u Unique: suppresses all but one in each set of lines
having equal keys. If used with the -c option, checks
that there are no lines with duplicate keys in addi-
tion to checking that the input file is sorted.
-y kmem
(obsolete). This option was used to specify the amount
of main memory initially used by sort. Its functional-
ity is not appropriate for a virtual memory system;
memory usage for sort is now specified using the -S
option.
-z recsz
(obsolete). This option was used to prevent abnormal
termination when lines longer than the system-
dependent default buffer size are encountered. Because
sort automatically allocates buffers large enough to
hold the longest line, this option has no effect.
Ordering Options
The default sort order depends on the value of LC_COLLATE.
If LC_COLLATE is set to C, sorting will be in ASCII order.
If LC_COLLATE is set to en_US, sorting is case insensitive
except when the two strings are otherwise equal and one has
an uppercase letter earlier than the other. Other locales
will have other sort orders.
The following options override the default ordering rules.
When ordering options appear independent of any key field
specifications, the requested field ordering rules are
applied globally to all sort keys. When attached to a
specific key (see Sort Key Options), the specified ordering
options override all global ordering options for that key.
In the obsolescent forms, if one or more of these options
follows a +pos1 option, it will affect only the key field
specified by that preceding option.
-d ``Dictionary'' order: only letters, digits, and blanks
(spaces and tabs) are significant in comparisons.
-f Folds lower-case letters into upper case.
-i Ignores non-printable characters.
-M Compares as months. The first three non-blank charac-
ters of the field are folded to upper case and com-
pared. For example, in English the sorting order is
"JAN" < "FEB" < ... < "DEC". Invalid fields compare
low to "JAN". The -M option implies the -b option (see
below).
-n Restricts the sort key to an initial numeric string,
consisting of optional blank characters, optional
minus sign, and zero or more digits with an optional
radix character and thousands separators (as defined
in the current locale), which will be sorted by arith-
metic value. An empty digit string is treated as
zero. Leading zeros and signs on zeros do not affect
ordering.
-r Reverses the sense of comparisons.
Field Separator Options
The treatment of field separators can be altered using the
following options:
-b Ignores leading blank characters when determining the
starting and ending positions of a restricted sort
key. If the -b option is specified before the first
sort key option, it is applied to all sort key
options. Otherwise, the -b option can be attached
independently to each -k field_start, field_end, or
+pos1 or -pos2 option-argument (see below).
-t char
Use char as the field separator character. char is not
considered to be part of a field (although it can be
included in a sort key). Each occurrence of char is
significant (for example, <char><char> delimits an
empty field). If -t is not specified, blank characters
are used as default field separators; each maximal
non-empty sequence of blank characters that follows a
non-blank character is a field separator.
Sort Key Options
Sort keys can be specified using the options:
-k keydef
The keydef argument is a restricted sort key field
definition. The format of this definition is:
-k field_start [type] [,field_end [type] ]
where:
field_start and field_end
define a key field restricted to a portion of the
line.
type is a modifier from the list of characters bdfiMnr. The
b modifier behaves like the -b option, but applies
only to the field_start or field_end to which it is
attached and characters within a field are counted
from the first non-blank character in the field. (This
applies separately to first_character and
last_character.) The other modifiers behave like the
corresponding options, but apply only to the key field
to which they are attached. They have this effect if
specified with field_start, field_end or both. If any
modifier is attached to a field_start or to a
field_end, no option applies to either.
When there are multiple key fields, later keys are compared
only after all earlier keys compare equal. Except when the
-u option is specified, lines that otherwise compare equal
are ordered as if none of the options -d, -f, -i, -n or -k
were present (but with -r still in effect, if it was speci-
fied) and with all bytes in the lines significant to the
comparison.
The notation:
-k field_start[type][,field_end[type]]
defines a key field that begins at field_start and ends at
field_end inclusive, unless field_start falls beyond the end
of the line or after field_end, in which case the key field
is empty. A missing field_end means the last character of
the line.
A field comprises a maximal sequence of non-separating char-
acters and, in the absence of option -t, any preceding field
separator.
The field_start portion of the keydef option-argument has
the form:
field_number[.first_character]
Fields and characters within fields are numbered starting
with 1. field_number and first_character, interpreted as
positive decimal integers, specify the first character to be
used as part of a sort key. If .first_character is omitted,
it refers to the first character of the field.
The field_end portion of the keydef option-argument has the
form:
field_number[.last_character]
The field_number is as described above for field_start.
last_character, interpreted as a non-negative decimal
integer, specifies the last character to be used as part of
the sort key. If last_character evaluates to zero or
.last_character is omitted, it refers to the last character
of the field specified by field_number.
If the -b option or b type modifier is in effect, characters
within a field are counted from the first non-blank charac-
ter in the field. (This applies separately to
first_character and last_character.)
[+pos1 [-pos2]]
(obsolete). Provide functionality equivalent to the
-kkeydef option.
pos1 and pos2 each have the form m.n optionally fol-
lowed by one or more of the flags bdfiMnr. A starting
position specified by +m.n is interpreted to mean the
n+1st character in the m+1st field. A missing .n means
.0, indicating the first character of the m+1st field.
If the b flag is in effect n is counted from the first
non-blank in the m+1st field; +m.0b refers to the
first non-blank character in the m+1st field.
A last position specified by -m.n is interpreted to
mean the nth character (including separators) after
the last character of the mth field. A missing .n
means .0, indicating the last character of the mth
field. If the b flag is in effect n is counted from
the last leading blank in the m+1st field; -m.1b
refers to the first non-blank in the m+1st field.
The fully specified +pos1 -pos2 form with type modif-
iers T and U:
+w.xT -y.zU
is equivalent to:
undefined (z==0 & U contains b & -t is present)
-k w+1.x+1T,y.0U (z==0 otherwise)
-k w+1.x+1T,y+1.zU (z > 0)
Implementations support at least nine occurrences of
the sort keys (the -k option and obsolescent +pos1 and
-pos2) which are significant in command line order. If
no sort key is specified, a default sort key of the
entire line is used.
OPERANDS
The following operand is supported:
file A path name of a file to be sorted, merged or checked.
If no file operands are specified, or if a file
operand is -, the standard input will be used.
USAGE
See largefile(5) for the description of the behavior of sort
when encountering files greater than or equal to 2 Gbyte ( 2
**31 bytes).
EXAMPLES
In the following examples, first the preferred and then the
obsolete way of specifying sort keys are given as an aid to
understanding the relationship between the two forms.
Example 1: Sorting with the second field as a sort key
Either of the following commands sorts the contents of
infile with the second field as the sort key:
example% sort -k 2,2 infile
example% sort +1 -2 infile
Example 2: Sorting in reverse order
Either of the following commands sorts, in reverse order,
the contents of infile1 and infile2, placing the output in
outfile and using the second character of the second field
as the sort key (assuming that the first character of the
second field is the field separator):
example% sort -r -o outfile -k 2.2,2.2 infile1 infile2
example% sort -r -o outfile +1.1 -1.2 infile1 infile2
Example 3: Sorting using a specified character in one of the
files
Either of the following commands sorts the contents of
infile1 and infile2 using the second non-blank character of
the second field as the sort key:
example% sort -k 2.2b,2.2b infile1 infile2
example% sort +1.1b -1.2b infile1 infile2
Example 4: Sorting by numeric user ID
Either of the following commands prints the passwd(4) file
(user database) sorted by the numeric user ID (the third
colon-separated field):
example% sort -t : -k 3,3n /etc/passwd
example% sort -t : +2 -3n /etc/passwd
Example 5: Printing sorted lines excluding lines that dupli-
cate a field
Either of the following commands prints the lines of the
already sorted file infile, suppressing all but one
occurrence of lines having the same third field:
example% sort -um -k 3.1,3.0 infile
example% sort -um +2.0 -3.0 infile
Example 6: Sorting by host IP address
Either of the following commands prints the hosts(4) file
(IPv4 hosts database), sorted by the numeric IP address (the
first four numeric fields):
example$ sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n /etc/hosts
example$ sort -t . +0 -1n +1 -2n +2 -3n +3 -4n /etc/hosts
Since '.' is both the field delimiter and, in many locales,
the decimal separator, failure to specify both ends of the
field will lead to results where the second field is inter-
preted as a fractional portion of the first, and so forth.
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment
variables that affect the execution of sort: LANG, LC_ALL,
LC_COLLATE, LC_MESSAGES, and NLSPATH.
LC_CTYPE
Determine the locale for the interpretation of
sequences of bytes of text data as characters (for
example, single- versus multi-byte characters in argu-
ments and input files) and the behavior of character
classification for the -b, -d, -f, -i and -n options.
LC_NUMERIC
Determine the locale for the definition of the radix
character and thousands separator for the -n option.
EXIT STATUS
The following exit values are returned:
0 All input files were output successfully, or -c was
specified and the input file was correctly sorted.
1 Under the -c option, the file was not ordered as
specified, or if the -c and -u options were both
specified, two input lines were found with equal keys.
>1 An error occurred.
FILES
/var/tmp/stm???
temporary files
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
/usr/bin/sort
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWesu |
|_____________________________|_____________________________|
| CSI | Enabled |
|_____________________________|_____________________________|
/usr/xpg4/bin/sort
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWxcu4 |
|_____________________________|_____________________________|
| CSI | Enabled |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
SEE ALSO
comm(1), join(1), uniq(1), nl_langinfo(3C), strftime(3C),
hosts(4), passwd(4), attributes(5), environ(5), large-
file(5), standards(5)
DIAGNOSTICS
Comments and exits with non-zero status for various trouble
conditions (for example, when input lines are too long), and
for disorders discovered under the -c option.
NOTES
When the last line of an input file is missing a new-line
character, sort appends one, prints a warning message, and
continues.
sort does not guarantee preservation of relative line order-
ing on equal keys.
One can tune sort performance for a specific scenario using
the -S option. However, one should note in particular that
sort has greater knowledge of how to use a finite amount of
memory for sorting than the virtual memory system. Thus, a
sort invoked to request an extremely large amount of memory
via the -S option could perform extremely poorly.
As noted, certain of the field modifiers (such as -M and -d)
cause the interpretation of input data to be done with
reference to locale-specific settings. The results of this
interpretation can be unexpected if one's expectations are
not aligned with the conventions established by the locale.
In the case of the month keys, sort does not attempt to com-
pensate for "approximate" month abbreviations. The precise
month abbreviations from nl_langinfo(3C) or strftime(3C) are
the only ones recognized. For printable or dictionary order,
if these concepts are not well-defined by the locale, an
empty sort key may be the result, leading to the next key
being the significant one for determining the appropriate
ordering.
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