split [-l line_count][-a
suffix_length][file[name]]
split -b n[k|m][-a
suffix_length][file[name]]
The split utility shall read an input file and write one 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.
The split utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
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.
The following operands shall be supported:
Any file can be used as input.
The following environment variables shall affect the execution of split:
The standard error shall be used only for diagnostic messages.
The output files contain portions of the original input file; otherwise, unchanged.
The following exit values shall be returned:
Default.
The following sections are informative.
In the following examples foo is a text file that contains 5000 lines.
split foo
split -a 3 foo
split -a 4 -l 2000 foo bar_
split -a 5 -b 20k foo
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 ). Upon reconsideration of the purpose of the User Portability Extension, 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.