 |
Charles Steinkuehler's LEAF/LRP Website |
|
sort.1NAME
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 documentation is no longer being maintained and may
be inaccurate or incomplete. The Texinfo documentation is
now the authoritative source.
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 ordering options were specified at all), sort com
pares 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 restric
tions 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 directory 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 charac
ters except letters, digits and blanks when sort
ing.
-f Fold lower case characters into the equivalent
upper case characters when sorting so that, for
example, `b' is sorted the same way `B' is.
-i Ignore characters outside the ASCII range 040-0176
octal (inclusive) when sorting.
-M An initial string, consisting of any amount of
white space, followed 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 out
put instead of later.
Other options are:
-o output-file
Write output to output-file instead of to the stan
dard 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 charac
ter. That is to say, given the input line ` foo
bar', sort breaks it into fields ` foo' and ` bar'.
The field separator 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 sort
ing 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
numbered 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 posi
tion 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 previ
ous 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 successfully.
COMPATIBILITY
Historical (BSD and System V) implementations of sort have
differed in their interpretation of some options, particu
larly -b, -f, and -n. GNU sort follows the POSIX behav
ior, 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!
Man(1) output converted with man2html |