разбить файл на части (split a file into pieces)
Пролог (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.
Имя (Name)
split — split a file into pieces
Синопсис (Synopsis)
split [-l line_count] [-a suffix_length] [file [name]]
split -b n[k|m] [-a suffix_length] [file [name]]
Описание (Description)
The split utility shall read an input file and write zero or more
output files. The default size of each output file shall be 1000
lines. The size of the output files can be modified by
specification of the -b or -l options. Each output file shall be
created with a unique suffix. The suffix shall consist of exactly
suffix_length lowercase letters from the POSIX locale. The
letters of the suffix shall be used as if they were a base-26
digit system, with the first suffix to be created consisting of
all 'a' characters, the second with a 'b' replacing the last 'a',
and so on, until a name of all 'z' characters is created. By
default, the names of the output files shall be 'x', followed by
a two-character suffix from the character set as described above,
starting with "aa", "ab", "ac", and so on, and continuing until
the suffix "zz", for a maximum of 676 files.
If the number of files required exceeds the maximum allowed by
the suffix length provided, such that the last allowable file
would be larger than the requested size, the split utility shall
fail after creating the last file with a valid suffix; split
shall not delete the files it created with valid suffixes. If the
file limit is not exceeded, the last file created shall contain
the remainder of the input file, and may be smaller than the
requested size. If the input is an empty file, no output file
shall be created and this shall not be considered to be an error.
Параметры (Options)
The split utility shall conform to the Base Definitions volume of
POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
-a suffix_length
Use suffix_length letters to form the suffix portion of
the filenames of the split file. If -a is not
specified, the default suffix length shall be two. If
the sum of the name operand and the suffix_length
option-argument would create a filename exceeding
{NAME_MAX} bytes, an error shall result; split shall
exit with a diagnostic message and no files shall be
created.
-b n Split a file into pieces n bytes in size.
-b nk Split a file into pieces n*1024 bytes in size.
-b nm Split a file into pieces n*1048576 bytes in size.
-l line_count
Specify the number of lines in each resulting file
piece. The line_count argument is an unsigned decimal
integer. The default is 1000. If the input does not end
with a <newline>, the partial line shall be included in
the last output file.
Операнды (Operands)
The following operands shall be supported:
file The pathname of the ordinary file to be split. If no
input file is given or file is '-', the standard input
shall be used.
name The prefix to be used for each of the files resulting
from the split operation. If no name argument is given,
'x' shall be used as the prefix of the output files.
The combined length of the basename of prefix and
suffix_length cannot exceed {NAME_MAX} bytes. See the
OPTIONS section.
Стандартный ввод (Stdin)
See the INPUT FILES section.
Входные файлы (Input files)
Any file can be used as input.
Переменные окружения (Environment variables)
The following environment variables shall affect the execution of
split:
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base
Definitions volume of POSIX.1‐2017, Section 8.2,
Internationalization Variables 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_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).
LC_MESSAGES
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to
standard error.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
Асинхронные события (Asynchronous events)
Default.
Стандартный вывод (Stdout)
Not used.
Стандартный вывод сообщений (Stderr)
The standard error shall be used only for diagnostic messages.
Выходные файлы (Output files)
The output files contain portions of the original input file;
otherwise, unchanged.
Расширенное описание (Extended description)
None.
Статус выхода (Exit)
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
Последствия ошибок (Consequences of errors)
Default.
The following sections are informative.
Использование в приложениях (Application usage)
None.
Примеры (Examples)
In the following examples foo is a text file that contains 5000
lines.
1. Create five files, xaa, xab, xac, xad, and xae:
split foo
2. Create five files, but the suffixed portion of the created
files consists of three letters, xaaa, xaab, xaac, xaad, and
xaae:
split -a 3 foo
3. Create three files with four-letter suffixes and a supplied
prefix, bar_aaaa, bar_aaab, and bar_aaac:
split -a 4 -l 2000 foo bar_
4. Create as many files as are necessary to contain at most
20*1024 bytes, each with the default prefix of x and a five-
letter suffix:
split -a 5 -b 20k foo
Обоснование (Rationale)
The -b option was added to provide a mechanism for splitting
files other than by lines. While most uses of the -b option are
for transmitting files over networks, some believed it would have
additional uses.
The -a option was added to overcome the limitation of being able
to create only 676 files.
Consideration was given to deleting this utility, using the
rationale that the functionality provided by this utility is
available via the csplit utility (see csplit(1p)). Upon
reconsideration of the purpose of the User Portability Utilities
option, it was decided to retain both this utility and the csplit
utility because users use both utilities and have historical
expectations of their behavior. Furthermore, the splitting on
byte boundaries in split cannot be duplicated with the historical
csplit.
The text ``split shall not delete the files it created with valid
suffixes'' would normally be assumed, but since the related
utility, csplit, does delete files under some circumstances, the
historical behavior of split is made explicit to avoid
misinterpretation.
Earlier versions of this standard allowed a -line_count option.
This form is no longer specified by POSIX.1‐2008 but may be
present in some implementations.
Будущие направления (Future directions)
None.
Смотри также (See also)
csplit(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines
