sort(1) manual page
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sort - sort, merge, or sequence check text files
/usr/bin/sort
[ -cmu ] [ -o output ] [ -T directory ] [ -y [ kmem ]] [ -z recsz ] [ -dfiMnr
] [ -b ] [ -t char ] [ -k keydef ] [ +pos1 [ -pos2 ]] [ file...]
/usr/xpg4/bin/sort
[ -cmu ] [ -o output ] [ -T directory ] [ -y [ kmem ]] [ -z recsz ] [ -dfiMnr
] [ -b ] [ -t char ] [ -k keydef ] [ +pos1 [ -pos2 ]] [ file...]
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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.
The
following options alter the default behavior:
- -c
- Check that
the single input file is ordered as specified 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.
- -c
- Same as
/usr/bin/sort except no output is produced under any circumstances.
- -m
- Merge only. The input files are assumed to be already sorted.
- -u
- Unique: suppress
all but one in each set of lines having equal keys. If used with the -c option,
check that there are no lines with duplicate keys in addition to checking
that the input file is sorted.
- -o output
- Specify 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.
- -T directory
- The directory argument is the name of
a directory in which to place temporary files.
- -y kmem
- The amount of main
memory initially used by sort. If this option is omitted, sort begins using
a system default memory size, and continues to use more space as needed.
If kmem is present, sort will start using that number of Kbytes of memory,
unless the administrative minimum or maximum is exceeded, in which case
the corresponding extremum will be used. Thus, -y 0 is guaranteed to start
with minimum memory. -y with no kmem argument starts with maximum memory.
- -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.
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
- Fold lower-case
letters into upper case.
- -i
- Ignore non-printable characters.
- -M
- Compare as months. The first three non-blank characters of the field are
folded to upper case and compared. 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
- Restrict 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
arithmetic value. An empty digit string is treated as zero. Leading zeros
and signs on zeros do not affect ordering.
- -r
- Reverse the sense of comparisons.
The treatment of field separators can be altered
using the following options:
- -b
- Ignore 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 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 specified) 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
characters 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 character
in the field. (This applies separately to first_character and last_character.)
- [+pos1[-pos2]]
- (obsolete). Provide functionality equivalent to the -k keydef
option.
- pos1
- and pos2 each have the form m.n optionally followed 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
modifiers 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.
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.
In the following examples,
non-obsolescent and obsolescent ways of specifying sort keys are given as
an aid to understanding the relationship between the two forms.
Either of
the following commands sorts the contents of infile with the second field
as the sort key:
example% sort -k 2,2 infileexample% sort +1 -2 infile
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 infile2example% sort -r -o outfile
+1.1 -1.2 infile1 infile2
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 infile2example% sort +1.1b -1.2b infile1 infile2
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/passwdexample% sort -t : +2 -3n /etc/passwd
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 infileexample% sort -um +2.0 -3.0 infile
See
environ(5)
for descriptions of the following environment variables that
affect the execution of sort: LC_COLLATE
, LC_MESSAGES
, and NLSPATH
.
- LC_CTYPE
- Determine the locale for 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.
The
following exit values are returned:
- All input files were output successfully,
or -c was specified and the input file was correctly sorted.
- 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.
- /var/tmp/stm???
- temporary files
comm(1)
, join(1)
,
uniq(1)
, passwd(4)
environ(5)
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.
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 ordering on equal keys.
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