The Single UNIX ® Specification, Version 2
Copyright © 1997 The Open Group


split - split files into pieces


split [-l line_count][-a suffix_length][file[name]]

split -b n[k|m][-a suffix_length][file[name]]

split [-line_count][-a suffix_length][file[name]]


The split utility reads an input file and writes one or more output files. The default size of each output file is 1000 lines. The size of the output files can be modified by specification of the -b or -l options. Each output file is created with a unique suffix. The suffix consists of exactly suffix_length lower-case letters from the POSIX locale. The letters of the suffix are 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 are 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 will fail after creating the last file with a valid suffix; split will not delete the files it created with valid suffixes. If the file limit is not exceeded, the last file created will contain the remainder of the input file, and may be smaller than the requested size.


The split utility supports the XBD specification, Utility Syntax Guidelines  except that the obsolescent version allows a multi-digit option, -line_count.

The following options are 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 is two. If the sum of the name operand and the suffix_length option-argument would create a filename exceeding {NAME_MAX} bytes, an error will result; split will exit with a diagnostic message and no files will 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 character, the partial line will be included in the last output file.


The following operands are supported:
The pathname of the ordinary file to be split. If no input file is given or file is "-", the standard input will be used.
The prefix to be used for each of the files resulting from the split operation. If no name argument is given, x will 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.


See the INPUT FILES section.


Any file can be used as input.


The following environment variables affect the execution of split:
Provide a default value for the internationalisation variables that are unset or null. If LANG is unset or null, the corresponding value from the implementation-dependent default locale will be used. If any of the internationalisation variables contains an invalid setting, the utility will behave as if none of the variables had been defined.
If set to a non-empty string value, override the values of all the other internationalisation variables.
Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single- as opposed to multi-byte characters in arguments and input files).
Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.
Determine the location of message catalogues for the processing of LC_MESSAGES .




Not used.


Used only for diagnostic messages.


The output files contain portions of the original input file, otherwise unchanged.




The following exit values are returned:
Successful completion.
An error occurred.






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





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Copyright © 1997 The Open Group
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