sort man page on CentOS

Man page or keyword search:  
man Server   8420 pages
apropos Keyword Search (all sections)
Output format
CentOS logo
[printable version]

SORT(P)			   POSIX Programmer's Manual		       SORT(P)

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the	 corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.

NAME
       sort - sort, merge, or sequence check text files

SYNOPSIS
       sort [-m][-o output][-bdfinru][-t char][-k keydef]... [file...]

       sort -c [-bdfinru][-t char][-k keydef][file]

DESCRIPTION
       The sort utility shall perform one of the following functions:

	1. Sort lines of all the named files together and write the result  to
	   the specified output.

	2. Merge  lines	 of all the named (presorted) files together and write
	   the result to the specified output.

	3. Check that a single input file is correctly presorted.

       Comparisons shall be based on one or more sort keys extracted from each
       line  of	 input	(or, if no sort keys are specified, the entire line up
       to, but not including, the terminating <newline>), and  shall  be  per‐
       formed using the collating sequence of the current locale.

OPTIONS
       The  sort  utility  shall  conform  to  the  Base Definitions volume of
       IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines, and  the
       -k keydef option should follow the -b, -d, -f, -i, -n, and -r options.

       The following options shall be supported:

       -c     Check  that the single input file is ordered as specified by the
	      arguments and the collating sequence of the current  locale.  No
	      output shall be produced; only the exit code shall be affected.

       -m     Merge  only;  the	 input	file  shall  be	 assumed to be already
	      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.

       -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.

       The  following  options shall override the default ordering rules. When
       ordering options appear independent of any  key	field  specifications,
       the  requested  field  ordering	rules shall be applied globally to all
       sort keys. When attached to a specific  key  (see  -k),	the  specified
       ordering	 options  shall	 override all global ordering options for that
       key.

       -d     Specify that only <blank>s and alphanumeric characters,  accord‐
	      ing to the current setting of LC_CTYPE , shall be significant in
	      comparisons. The behavior is undefined for a sort key  to	 which
	      -i or -n also applies.

       -f     Consider	all  lowercase	characters that have uppercase equiva‐
	      lents, according to the current setting of LC_CTYPE , to be  the
	      uppercase equivalent for the purposes of comparison.

       -i     Ignore  all  characters that are non-printable, according to the
	      current setting of LC_CTYPE .

       -n     Restrict the sort key to an initial numeric  string,  consisting
	      of optional <blank>s, optional minus sign, and zero or more dig‐
	      its with an optional radix character  and	 thousands  separators
	      (as  defined  in	the  current locale), which shall be sorted by
	      arithmetic value. An empty digit	string	shall  be  treated  as
	      zero.   Leading zeros and signs on zeros shall not affect order‐
	      ing.

       -r     Reverse the sense of comparisons.

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

       -b     Ignore leading <blank>s when determining the starting and ending
	      positions	 of  a restricted sort key. If the -b option is speci‐
	      fied before the first -k option, it shall be applied to  all  -k
	      options.	Otherwise, the -b option can be attached independently
	      to each -k field_start or field_end option-argument (see below).

       -t  char
	      Use char as the field separator character;  char	shall  not  be
	      considered to be part of a field (although it can be included in
	      a sort key). Each occurrence of char shall be  significant  (for
	      example,	<char><char>  delimits	an  empty field). If -t is not
	      specified, <blank>s shall be used as default  field  separators;
	      each  maximal non-empty sequence of <blank>s that follows a non-
	      <blank> shall be 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:

	      field_start[type][,field_end[type]]

       where field_start and field_end define a key field restricted to a por‐
       tion of the line (see the EXTENDED DESCRIPTION section), and type is  a
       modifier	 from the list of characters 'b' , 'd' , 'f' , 'i' , 'n' , 'r'
       . The 'b' modifier shall behave like the -b  option,  but  shall	 apply
       only  to	 the  field_start  or  field_end to which it is attached.  The
       other modifiers shall behave like the corresponding options, but	 shall
       apply only to the key field to which they are attached; they shall 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
       shall apply to either. Implementations  shall  support  at  least  nine
       occurrences  of	the  -k	 option, which shall be significant in command
       line order. If no -k option is specified, a default  sort  key  of  the
       entire line shall be used.

       When  there  are multiple key fields, later keys shall be compared only
       after all earlier keys compare equal. Except  when  the	-u  option  is
       specified,  lines  that	otherwise compare equal shall be 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 order in which lines that still com‐
       pare equal are written is unspecified.

OPERANDS
       The following operand shall be supported:

       file   A	 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 shall be used.

STDIN
       The  standard  input  shall be used only if no file operands are speci‐
       fied, or if a file operand is '-' .  See the INPUT FILES section.

INPUT FILES
       The input files shall be text files, except that the sort utility shall
       add  a  <newline>  to  the end of a file ending with an incomplete last
       line.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of sort:

       LANG   Provide a default value for the  internationalization  variables
	      that  are	 unset	or  null.  (See the Base Definitions volume of
	      IEEE Std 1003.1-2001, Section  8.2,  Internationalization	 Vari‐
	      ables  for the precedence of internationalization variables used
	      to determine the values of locale categories.)

       LC_ALL If set to a non-empty string value, override the values  of  all
	      the other internationalization variables.

       LC_COLLATE

	      Determine the locale for ordering rules.

       LC_CTYPE
	      Determine	 the  locale  for  the	interpretation of sequences of
	      bytes of text data as characters (for  example,  single-byte  as
	      opposed  to  multi-byte characters in arguments and input files)
	      and the behavior of character classification for the -b, -d, -f,
	      -i, and -n options.

       LC_MESSAGES
	      Determine	 the  locale  that should be used to affect the format
	      and contents of diagnostic messages written to standard error.

       LC_NUMERIC

	      Determine the locale for the definition of the  radix  character
	      and thousands separator for the -n option.

       NLSPATH
	      Determine the location of message catalogs for the processing of
	      LC_MESSAGES .

ASYNCHRONOUS EVENTS
       Default.

STDOUT
       Unless the -o or -c options are in effect, the  standard	 output	 shall
       contain the sorted input.

STDERR
       The  standard  error  shall  be used for diagnostic messages. A warning
       message about correcting an incomplete last line of an input  file  may
       be generated, but need not affect the final exit status.

OUTPUT FILES
       If the -o option is in effect, the sorted input shall be written to the
       file output.

EXTENDED DESCRIPTION
       The notation:

	      -k field_start[type][,field_end[type]]

       shall define 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	 miss‐
       ing field_end shall mean 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  shall  have  the
       form:

	      field_number[.first_character]

       Fields  and characters within fields shall be numbered starting with 1.
       The field_number and first_character pieces,  interpreted  as  positive
       decimal	integers, shall specify the first character to be used as part
       of a sort key. If .first_character is omitted, it shall	refer  to  the
       first character of the field.

       The  field_end  portion	of  the	 keydef option-argument shall have the
       form:

	      field_number[.last_character]

       The field_number shall be as  described	above  for  field_start.   The
       last_character  piece,  interpreted  as a non-negative decimal integer,
       shall specify the last character to be used as part of the sort key. If
       last_character  evaluates  to  zero  or	.last_character is omitted, it
       shall refer to the last character of the field specified by  field_num‐
       ber.

       If  the	-b option or b type modifier is in effect, characters within a
       field shall be counted from the first non- <blank> in the field.	 (This
       shall apply separately to first_character and last_character.)

EXIT STATUS
       The following exit values shall be 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.

CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       The default value for -t, <blank>, has different properties  from,  for
       example, -t "<space>". If a line contains:

	      <space><space>foo

       the  following treatment would occur with default separation as opposed
       to specifically selecting a <space>:

		      Field   Default		  -t "<space>"
		      1	      <space><space>foo	  empty
		      2	      empty		  empty
		      3	      empty		  foo

       The leading field separator itself is included in a field  when	-t  is
       not  used.  For	example,  this command returns an exit status of zero,
       meaning the input was already sorted:

	      sort -c -k 2 <<eof
	      y<tab>b
	      x<space>a
	      eof

       (assuming that a <tab> precedes the <space> in  the  current  collating
       sequence).  The	field  separator is not included in a field when it is
       explicitly set via -t. This is historical  practice  and	 allows	 usage
       such as:

	      sort -t "|" -k 2n <<eof
	      Atlanta|425022|Georgia
	      Birmingham|284413|Alabama
	      Columbia|100385|South Carolina
	      eof

       where  the  second  field  can  be correctly sorted numerically without
       regard to the non-numeric field separator.

       The wording in the OPTIONS section clarifies that the -b, -d,  -f,  -i,
       -n,  and -r options have to come before the first sort key specified if
       they are intended to apply  to  all  specified  keys.  The  way	it  is
       described  in  this  volume  of IEEE Std 1003.1-2001 matches historical
       practice, not historical documentation. The results are unspecified  if
       these options are specified after a -k option.

       The  -f option might not work as expected in locales where there is not
       a one-to-one mapping between an uppercase and a lowercase letter.

EXAMPLES
	1. The following command sorts the contents of infile with the	second
	   field as the sort key:

	   sort -k 2,2 infile

	2. The	following  command  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):

	   sort -r -o outfile -k 2.2,2.2 infile1 infile2

	3. The following command sorts the contents  of	 infile1  and  infile2
	   using the second non- <blank> of the second field as the sort key:

	   sort -k 2.2b,2.2b infile1 infile2

	4. The following command prints the System V password file (user data‐
	   base) sorted by the numeric	user  ID  (the	third  colon-separated
	   field):

	   sort -t : -k 3,3n /etc/passwd

	5. The	following  command prints the lines of the already sorted file
	   infile, suppressing all but one occurrence of lines having the same
	   third field:

	   sort -um -k 3.1,3.0 infile

RATIONALE
       Examples	 in  some historical documentation state that options -um with
       one input file keep the first in each set of  lines  with  equal	 keys.
       This  behavior  was deemed to be an implementation artifact and was not
       standardized.

       The -z option was omitted; it is not standard practice on most  systems
       and  is inconsistent with using sort to sort several files individually
       and then merge them together. The text concerning -z in historical doc‐
       umentation  appeared to require implementations to determine the proper
       buffer length during the sort phase of operation, but  not  during  the
       merge.

       The  -y	option	was omitted because of non-portability. The -M option,
       present in System V, was omitted because of non-portability in interna‐
       tional usage.

       An undocumented -T option exists in some implementations. It is used to
       specify	a  directory  for  intermediate	 files.	  Implementations  are
       encouraged  to  support	the  use  of  the  TMPDIR environment variable
       instead of adding an option to support this functionality.

       The -k option was added to satisfy two  objections.  First,  the	 zero-
       based  counting	used by sort is not consistent with other utility con‐
       ventions. Second, it did not meet syntax guideline requirements.

       Historical documentation indicates that "setting -n  implies  -b".  The
       description  of	-n  already  states that optional leading <blank>s are
       tolerated in doing the comparison.   If	-b  is	enabled,  rather  than
       implied,	 by -n, this has unusual side effects. When a character offset
       is used in a column of numbers (for example, to sort modulo 100),  that
       offset  is  measured relative to the most significant digit, not to the
       column. Based upon a recommendation from the  author  of	 the  original
       sort  utility,  the -b implication has been omitted from this volume of
       IEEE Std 1003.1-2001, and an application wishing to achieve the	previ‐
       ously mentioned side effects has to code the -b flag explicitly.

FUTURE DIRECTIONS
       None.

SEE ALSO
       comm   ,	  join	 ,   uniq   ,	the   System   Interfaces   volume  of
       IEEE Std 1003.1-2001, toupper()

COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),	The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the	referee document. The original Standard can be obtained online
       at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group		     2003			       SORT(P)
[top]

List of man pages available for CentOS

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net