Command Section
SORT(1)                 FreeBSD General Commands Manual                SORT(1)

     sort - sort or merge records (lines) of text and binary files

     sort [-bcCdfghiRMmnrsuVz] [-k field1[,field2]] [-S memsize] [-T dir] [-t
          char] [-o output] [file ...]
     sort --help
     sort --version

     The sort utility sorts text and binary files by lines.  A line is a
     record separated from the subsequent record by a newline (default) or NUL
     '\0' character (-z option).  A record can contain any printable or
     unprintable characters.  Comparisons are based on one or more sort keys
     extracted from each line of input, and are performed lexicographically,
     according to the current locale's collating rules and the specified
     command-line options that can tune the actual sorting behavior.  By
     default, if keys are not given, sort uses entire lines for comparison.

     The command line options are as follows:

     -c, --check, -C, --check=silent|quiet
             Check that the single input file is sorted.  If the file is not
             sorted, sort produces the appropriate error messages and exits
             with code 1, otherwise returns 0.  If -C or --check=silent is
             specified, sort produces no output.  This is a "silent" version
             of -c.

     -m, --merge
             Merge only.  The input files are assumed to be pre-sorted.  If
             they are not sorted the output order is undefined.

     -o output, --output=output
             Print the output to the output file instead of the standard

     -S size, --buffer-size=size
             Use size for the maximum size of the memory buffer.  Size
             modifiers %,b,K,M,G,T,P,E,Z,Y can be used.  If a memory limit is
             not explicitly specified, sort takes up to about 90% of available
             memory.  If the file size is too big to fit into the memory
             buffer, the temporary disk files are used to perform the sorting.

     -T dir, --temporary-directory=dir
             Store temporary files in the directory dir.  The default path is
             the value of the environment variable TMPDIR or /var/tmp if
             TMPDIR is not defined.

     -u, --unique
             Unique keys.  Suppress all lines that have a key that is equal to
             an already processed one.  This option, similarly to -s, implies
             a stable sort.  If used with -c or -C, sort also checks that
             there are no lines with duplicate keys.

     -s      Stable sort.  This option maintains the original record order of
             records that have an equal key.  This is a non-standard feature,
             but it is widely accepted and used.

             Print the version and silently exits.

     --help  Print the help text and silently exits.

     The following options override the default ordering rules.  When ordering
     options appear independently of key field specifications, they apply
     globally to all sort keys.  When attached to a specific key (see -k), the
     ordering options override all global ordering options for the key they
     are attached to.

     -b, --ignore-leading-blanks
             Ignore leading blank characters when comparing lines.

     -d, --dictionary-order
             Consider only blank spaces and alphanumeric characters in

     -f, --ignore-case
             Convert all lowercase characters to their uppercase equivalent
             before comparison, that is, perform case-independent sorting.

     -g, --general-numeric-sort, --sort=general-numeric
             Sort by general numerical value.  As opposed to -n, this option
             handles general floating points.  It has a more permissive format
             than that allowed by -n but it has a significant performance

     -h, --human-numeric-sort, --sort=human-numeric
             Sort by numerical value, but take into account the SI suffix, if
             present.  Sort first by numeric sign (negative, zero, or
             positive); then by SI suffix (either empty, or `k' or `K', or one
             of `MGTPEZY', in that order); and finally by numeric value.  The
             SI suffix must immediately follow the number.  For example,
             '12345K' sorts before '1M', because M is "larger" than K.  This
             sort option is useful for sorting the output of a single
             invocation of 'df' command with -h or -H options (human-

     -i, --ignore-nonprinting
             Ignore all non-printable characters.

     -M, --month-sort, --sort=month
             Sort by month abbreviations.  Unknown strings are considered
             smaller than the month names.

     -n, --numeric-sort, --sort=numeric
             Sort fields numerically by arithmetic value.  Fields are supposed
             to have optional blanks in the beginning, an optional minus sign,
             zero or more digits (including decimal point and possible
             thousand separators).

     -R, --random-sort, --sort=random
             Sort by a random order.  This is a random permutation of the
             inputs except that the equal keys sort together.  It is
             implemented by hashing the input keys and sorting the hash
             values.  The hash function is chosen randomly.  The hash function
             is randomized by /dev/random content, or by file content if it is
             specified by --random-source.  Even if multiple sort fields are
             specified, the same random hash function is used for all of them.

     -r, --reverse
             Sort in reverse order.

     -V, --version-sort
             Sort version numbers.  The input lines are treated as file names
             in form PREFIX VERSION SUFFIX, where SUFFIX matches the regular
             expression "(.([A-Za-z~][A-Za-z0-9~]*)?)*".  The files are
             compared by their prefixes and versions (leading zeros are
             ignored in version numbers, see example below).  If an input
             string does not match the pattern, then it is compared using the
             byte compare function.  All string comparisons are performed in C
             locale, the locale environment setting is ignored.


             $ ls sort* | sort -V









     The treatment of field separators can be altered using these options:

     -b, --ignore-leading-blanks
             Ignore leading blank space when determining the start and end of
             a restricted sort key (see -k).  If -b is specified before the
             first -k option, it applies globally to all key specifications.
             Otherwise, -b can be attached independently to each field
             argument of the key specifications.  -b.

     -k field1[,field2], --key=field1[,field2]
             Define a restricted sort key that has the starting position
             field1, and optional ending position field2 of a key field.  The
             -k option may be specified multiple times, in which case
             subsequent keys are compared when earlier keys compare equal.
             The -k option replaces the obsolete options +pos1 and -pos2, but
             the old notation is also supported.

     -t char, --field-separator=char
             Use char as a field separator character.  The initial char is not
             considered to be part of a field when determining key offsets.
             Each occurrence of char is significant (for example, ``charchar''
             delimits an empty field).  If -t is not specified, the default
             field separator is a sequence of blank space characters, and
             consecutive blank spaces do not delimit an empty field, however,
             the initial blank space is considered part of a field when
             determining key offsets.  To use NUL as field separator, use -t

     -z, --zero-terminated
             Use NUL as record separator.  By default, records in the files
             are supposed to be separated by the newline characters.  With
             this option, NUL ('\0') is used as a record separator character.

     Other options:

             Specify maximum number of files that can be opened by sort at
             once.  This option affects behavior when having many input files
             or using temporary files.  The default value is 16.

             Use PROGRAM to compress temporary files.  PROGRAM must compress
             standard input to standard output, when called without arguments.
             When called with argument -d it must decompress standard input to
             standard output.  If PROGRAM fails, sort must exit with error.
             An example of PROGRAM that can be used here is bzip2.

             In random sort, the file content is used as the source of the
             'seed' data for the hash function choice.  Two invocations of
             random sort with the same seed data will use the same hash
             function and will produce the same result if the input is also
             identical.  By default, file /dev/random is used.

             Print some extra information about the sorting process to the
             standard output.

             Take the input file list from the file filename.  The file names
             must be separated by NUL (like the output produced by the command
             "find ... -print0").

             Try to use radix sort, if the sort specifications allow.  The
             radix sort can only be used for trivial locales (C and POSIX),
             and it cannot be used for numeric or month sort.  Radix sort is
             very fast and stable.

             Use mergesort.  This is a universal algorithm that can always be
             used, but it is not always the fastest.

             Try to use quick sort, if the sort specifications allow.  This
             sort algorithm cannot be used with -u and -s.

             Try to use heap sort, if the sort specifications allow.  This
             sort algorithm cannot be used with -u and -s.

     --mmap  Try to use file memory mapping system call.  It may increase
             speed in some cases.

     The following operands are available:

     file    The pathname of a file to be sorted, merged, or checked.  If no
             file operands are specified, or if a file operand is -, the
             standard input is used.

     A field is defined as a maximal sequence of characters other than the
     field separator and record separator (newline by default).  Initial blank
     spaces are included in the field unless -b has been specified; the first
     blank space of a sequence of blank spaces acts as the field separator and
     is included in the field (unless -t is specified).  For example, all
     blank spaces at the beginning of a line are considered to be part of the
     first field.

     Fields are specified by the -k field1[,field2] command-line option.  If
     field2 is missing, the end of the key defaults to the end of the line.

     The arguments field1 and field2 have the form m.n (m,n > 0) and can be
     followed by one or more of the modifiers b, d, f, i, n, g, M and r, which
     correspond to the options discussed above.  When b is specified it
     applies only to field1 or field2 where it is specified while the rest of
     the modifiers apply to the whole key field regardless if they are
     specified only with field1 or field2 or both.  A field1 position
     specified by m.n is interpreted as the nth character from the beginning
     of the mth field.  A missing .n in field1 means `.1', indicating the
     first character of the mth field; if the -b option is in effect, n is
     counted from the first non-blank character in the mth field; m.1b refers
     to the first non-blank character in the mth field.  1.n refers to the nth
     character from the beginning of the line; if n is greater than the length
     of the line, the field is taken to be empty.

     nth positions are always counted from the field beginning, even if the
     field is shorter than the number of specified positions.  Thus, the key
     can really start from a position in a subsequent field.

     A field2 position specified by m.n is interpreted as the nth character
     (including separators) from the beginning of the mth field.  A missing .n
     indicates the last character of the mth field; m = 0 designates the end
     of a line.  Thus the option -k v.x,w.y is synonymous with the obsolete
     option +v-1.x-1 -w-1.y; when y is omitted, -k v.x,w is synonymous with
     +v-1.x-1 -w.0.  The obsolete +pos1 -pos2 option is still supported,
     except for -w.0b, which has no -k equivalent.

     LC_COLLATE  Locale settings to be used to determine the collation for
                 sorting records.

     LC_CTYPE    Locale settings to be used to case conversion and
                 classification of characters, that is, which characters are
                 considered whitespaces, etc.

                 Locale settings that determine the language of output
                 messages that sort prints out.

     LC_NUMERIC  Locale settings that determine the number format used in
                 numeric sort.

     LC_TIME     Locale settings that determine the month format used in month

     LC_ALL      Locale settings that override all of the above locale
                 settings.  This environment variable can be used to set all
                 these settings to the same value at once.

     LANG        Used as a last resort to determine different kinds of locale-
                 specific behavior if neither the respective environment
                 variable, nor LC_ALL are set.

     NLSPATH     Path to NLS catalogs.

     TMPDIR      Path to the directory in which temporary files will be
                 stored.  Note that TMPDIR may be overridden by the -T option.

                 If defined -t will not override the locale numeric symbols,
                 that is, thousand separators and decimal separators.  By
                 default, if we specify -t with the same symbol as the
                 thousand separator or decimal point, the symbol will be
                 treated as the field separator.  Older behavior was less
                 definite; the symbol was treated as both field separator and
                 numeric separator, simultaneously.  This environment variable
                 enables the old behavior.

     /var/tmp/.bsdsort.PID.*           Temporary files.
     /dev/random                       Default seed file for the random sort.

     The sort utility shall exit with one of the following values:

     0     Successfully sorted the input files or if used with -c or -C, the
           input file already met the sorting criteria.
     1     On disorder (or non-uniqueness) with the -c or -C options.
     2     An error occurred.

     comm(1), join(1), uniq(1)

     The sort utility is compliant with the IEEE Std 1003.1-2008 (``POSIX.1'')

     The flags [-ghRMSsTVz] are extensions to the POSIX specification.

     All long options are extensions to the specification, some of them are
     provided for compatibility with GNU versions and some of them are own

     The old key notations +pos1 and -pos2 come from older versions of sort
     and are still supported but their use is highly discouraged.

     A sort command first appeared in Version 3 AT&T UNIX.

     Gabor Kovesdan <[email protected]>,

     Oleg Moskalenko <[email protected]>

     This implementation of sort has no limits on input line length (other
     than imposed by available memory) or any restrictions on bytes allowed
     within lines.

     The performance depends highly on locale settings, efficient choice of
     sort keys and key complexity.  The fastest sort is with locale C, on
     whole lines, with option -s.  In general, locale C is the fastest, then
     single-byte locales follow and multi-byte locales as the slowest but the
     correct collation order is always respected.  As for the key
     specification, the simpler to process the lines the faster the search
     will be.

     When sorting by arithmetic value, using -n results in much better
     performance than -g so its use is encouraged whenever possible.

FreeBSD 11.1-RELEASE-p4         March 19, 2015         FreeBSD 11.1-RELEASE-p4
Command Section