Split (Unix)

{{Short description|UNIX text-processing utility program}} {{lowercase title}} {{Infobox software | name = split | logo = | screenshot = Split-example.png | screenshot size = | caption = Example of <code>split</code> usage | author = AT&T Bell Laboratories | developer = Various open-source and commercial developers | released = {{Start date and age|1973|2}} | latest release version = | latest release date = | programming language = C | operating system = Unix, Unix-like, Plan 9, IBM i | platform = Cross-platform | genre = Command | license = coreutils: GPLv3+<br />Plan 9: MIT License | website = }} '''<code>split</code>''' is a utility on Unix, Plan 9, and Unix-like operating systems most commonly used to split a computer file into two or more smaller files.

==History== The {{code|split}} command first appeared in Version 3 Unix<ref>{{man|1|split|FreeBSD}}</ref> and is part of the X/Open Portability Guide since issue 2 of 1987. It was inherited into the first version of POSIX.1 and the Single Unix Specification.<ref>{{man|cu|split|SUS}}</ref> The version of <code>split</code> bundled in GNU coreutils was written by Torbjorn Granlund and Richard Stallman.<ref>{{Cite web|url=https://linux.die.net/man/1/split|title=split(1): split file into pieces - Linux man page|website=linux.die.net|access-date=2019-01-24|archive-date=2018-09-24|archive-url=https://web.archive.org/web/20180924110847/https://linux.die.net/man/1/split|url-status=live}}</ref> The {{Mono|split}} command has also been ported to the IBM i operating system.<ref>{{cite web |title=IBM System i Version 7.2 Programming Qshell |language=en |author=IBM |website=IBM |author-link=IBM |url=https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_74/rzahz/rzahzpdf.pdf?view=kc |access-date=2020-09-05 |archive-date=2020-09-18 |archive-url=https://web.archive.org/web/20200918130823/https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_74/rzahz/rzahzpdf.pdf?view=kc |url-status=live }}</ref>

==Usage== The command-syntax is: <syntaxhighlight lang="bash"> split [OPTION] [INPUT [PREFIX]] </syntaxhighlight>

The default behavior of <code>split</code> is to generate output files of a fixed size, default 1000 lines. The files are named by appending ''aa'', ''ab'', ''ac'', etc. to ''output filename''. If ''output filename'' is not given, the default filename of ''x'' is used, for example, ''xaa'', ''xab'', etc. When a hyphen (''-'') is used instead of ''input filename'', data is derived from standard input. The files are typically rejoined using a utility such as cat.

Additional program options permit a maximum character count (instead of a line count), a maximum line length, how many incrementing characters in generated filenames, and whether to use letters or digits.

=== Split file into pieces === Create a file named "<code>myfile.txt</code>" with exactly 3,000 lines of data: <syntaxhighlight lang="console"> $ head -3000 < /dev/urandom > myfile.txt </syntaxhighlight>

Now, use the <code>split</code> command to break this file into pieces (note: unless otherwise specified, <code>split</code> will break the file into 1,000-line files): <syntaxhighlight lang="console"> $ split myfile.txt $ ls -l -rw-r--r-- 1 root root 761K Jun 16 18:17 myfile.txt -rw-r--r-- 1 root root 242K Jun 16 18:17 xaa -rw-r--r-- 1 root root 263K Jun 16 18:17 xab -rw-r--r-- 1 root root 256K Jun 16 18:17 xac $ wc --lines xa* 1000 xaa 1000 xab 1000 xac 3000 total </syntaxhighlight> As seen above, the <code>split</code> command has broken the original file (keeping the original intact) into three, equal in number of lines (i.e., 1,000), files: <code>xaa</code>, <code>xab</code>, and <code>xac</code>.

==See also== * csplit – splits by content rather than by size * File spanning * List of Unix commands

==References== {{Reflist}}

==External links== {{Wikibooks|Guide to Unix|Commands}} *{{man|cu|split|SUS}}

Category:Standard Unix programs Category:Unix SUS2008 utilities Category:Plan 9 commands Category:IBM i Qshell commands