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SORT(1)								       SORT(1)

NAME
       sort - sort lines of text files

SYNOPSIS
       sort  [-cmus]  [-t  separator] [-o output-file] [-T tempdir] [-bdfiMnr]
       [+POS1 [-POS2]] [-k POS1[,POS2]]	[file...]
       sort {--help,--version}

DESCRIPTION
       This manual page	documents  the	GNU  version  of  sort.	  sort	sorts,
       merges, or compares all the lines from the given	files, or the standard
       input if	no files are given.  A file name of `-'	means standard	input.
       By default, sort	writes the results to the standard output.

       sort has	three modes of operation: sort (the default), merge, and check
       for sortedness.	The following options change the operation mode:

       -c     Check whether the	given files are	already	sorted:	 if  they  are
	      not all sorted, print an error message and exit with a status of
	      1.

       -m     Merge the	given files by sorting them as a  group.   Each	 input
	      file  should already be individually sorted.  It always works to
	      sort instead of merge; merging is	provided because it is faster,
	      in the case where	it works.

       A  pair	of  lines  is compared as follows: if any key fields have been
       specified, sort compares	each pair of fields, in	the order specified on
       the command line, according to the associated ordering options, until a
       difference is found or no fields	are left.

       If any of the global options Mbdfinr are	given but no  key  fields  are
       specified,  sort	 compares  the	entire	lines  according to the	global
       options.

       Finally,	as a last resort when all keys compare equal (or if no	order-
       ing  options  were  specified  at all), sort compares the lines byte by
       byte in machine collating sequence.  The	last resort comparison	honors
       the -r global option.  The -s (stable) option disables this last-resort
       comparison so that lines	in which all fields compare equal are left  in
       their  original	relative  order.   If  no fields or global options are
       specified, -s has no effect.

       GNU sort	has no limits on input line length or  restrictions  on	 bytes
       allowed	within lines.  In addition, if the final byte of an input file
       is not a	newline, GNU sort silently supplies one.

       If the environment variable TMPDIR is set, sort uses it as  the	direc-
       tory in which to	put temporary files instead of the default, /tmp.  The
       -T tempdir option is another way	to select the directory	for  temporary
       files; it overrides the environment variable.

       The following options affect the	ordering of output lines.  They	may be
       specified globally or as	part of	a  specific  key  field.   If  no  key
       fields  are  specified,	global	options	 apply to comparison of	entire
       lines; otherwise	the global options are inherited by key	fields that do
       not specify any special options of their	own.

       -b     Ignore leading blanks when finding sort keys in each line.

       -d     Sort  in	`phone	directory' order: ignore all characters	except
	      letters, digits and blanks when sorting.

       -f     Fold lower case characters into the equivalent upper case	 char-
	      acters when sorting so that, for example,	`b' is sorted the same
	      way `B' is.

       -i     Ignore characters	outside	the ASCII range	040-0176 octal (inclu-
	      sive) when sorting.

       -M     An initial string, consisting of any amount of white space, fol-
	      lowed by three letters abbreviating a month name,	is  folded  to
	      UPPER  case  and	compared  in  the  order `JAN' < `FEB' < ... <
	      `DEC.'  Invalid names compare low	to valid names.

       -n     Compare according	to arithmetic value an initial numeric	string
	      consisting of optional white space, an optional -	sign, and zero
	      or more digits, optionally followed by a decimal point and  zero
	      or more digits.

       -r     Reverse the result of comparison,	so that	lines with greater key
	      values appear earlier in the output instead of later.

       Other options are:

       -o output-file
	      Write output to output-file instead of to	the  standard  output.
	      If  output-file  is  one of the input files, sort	copies it to a
	      temporary	file before sorting and	writing	the output to  output-
	      file.

       -t separator
	      Use  character separator as the field separator when finding the
	      sort keys	in each	line.  By default, fields are separated	by the
	      empty string between a non-whitespace character and a whitespace
	      character.  That is to say, given	the input  line	 `  foo	 bar',
	      sort breaks it into fields ` foo'	and ` bar'.  The field separa-
	      tor is not considered to be part of either the  field  preceding
	      or the field following it.

       -u     For  the default case or the -m option, only output the first of
	      a	sequence of lines that compare	equal.	 For  the  -c  option,
	      check that no pair of consecutive	lines compares equal.

       +POS1 [-POS2]
	      Specify  a  field	within each line to use	as a sorting key.  The
	      field consists of	the portion of the line	starting at  POS1  and
	      up  to  (but  not	 including) POS2 (or to	the end	of the line if
	      POS2 is not given).  The fields and character positions are num-
	      bered starting with 0.

       -k POS1[,POS2]
	      An alternate syntax for specifying sorting keys.	The fields and
	      character	positions are numbered starting	with 1.

       A position has the form f.c, where f is the number of the field to  use
       and  c  is  the number of the first character from the beginning	of the
       field (for +pos)	or from	the end	of the previous	field (for -pos).  The
       .c  part	 of  a position	may be omitted in which	case it	is taken to be
       the first character in the field.  If the -b option has been given, the
       .c  part	 of  a	field specification is counted from the	first nonblank
       character of the	field (for +pos) or from the first nonblank  character
       following the previous field (for -pos).

       A +pos or -pos argument may also	have any of the	option letters Mbdfinr
       appended	to it, in which	case the global	ordering options are not  used
       for that	particular field.  The -b option may be	independently attached
       to either or both of the	+pos and -pos parts of a field	specification,
       and  if	it is inherited	from the global	options	it will	be attached to
       both.  If a -n or -M option is used, thus implying a -b option, the  -b
       option  is  taken to apply to both the +pos and the -pos	parts of a key
       specification.  Keys may	span multiple fields.

       In addition, when GNU sort is invoked with exactly  one	argument,  the
       following options are recognized:

       --help Print  a usage message on	standard output	and exit successfully.

       --version
	      Print version information	on standard output then	exit  success-
	      fully.

COMPATIBILITY
       Historical  (BSD	and System V) implementations of sort have differed in
       their interpretation of some options, particularly -b, -f, and -n.  GNU
       sort  follows  the  POSIX  behavior, which is usually (but not always!)
       like the	System V behavior.  According to POSIX -n  no  longer  implies
       -b.   For  consistency,	-M has been changed in the same	way.  This may
       affect the meaning of character positions in  field  specifications  in
       obscure cases.  If this bites you the fix is to add an explicit -b.

BUGS
       The  different meaning of field numbers depending on whether -k is used
       is confusing.  It's all POSIX's fault!

FSF			      GNU Text Utilities		       SORT(1)

NAME | SYNOPSIS | DESCRIPTION | COMPATIBILITY | BUGS

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