CSPLIT(1)                  POSIX Programmer's Manual                 CSPLIT(1)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NAME
       csplit -- split files based on context

SYNOPSIS
       csplit [[-ks]] [[-f prefix]] [[-n number]] file arg...

DESCRIPTION
       The csplit utility shall read the file named by the file operand, write
       all or part of that file into other files as directed by the arg
       operands, and write the sizes of the files.

OPTIONS
       The csplit utility shall conform to the Base Definitions volume of
       POSIX.1-2017, Section 12.2, Utility Syntax Guidelines.

       The following options shall be supported:

       -f prefix Name the created files prefix0000, prefix0011, ..., prefixn.  The
                 default is xx00 ...  xxxx_n.  If the prefix argument would
                 create a filename exceeding {NAME_MAX} bytes, an error shall
                 result, csplit shall exit with a diagnostic message, and no
                 files shall be created.

       -k        Leave previously created files intact. By default, csplit
                 shall remove created files if an error occurs.

       -n number Use number decimal digits to form filenames for the file
                 pieces. The default shall be 2.

       -s        Suppress the output of file size messages.

OPERANDS
       The following operands shall be supported:

       file      The pathname of a text file to be split. If file is ''--'', the
                 standard input shall be used.

       Each arg operand can be one of the following:

       /rexp/[[offset]]
                 A file shall be created using the content of the lines from
                 the current line up to, but not including, the line that
                 results from the evaluation of the regular expression with
                 offset, if any, applied. The regular expression rexp shall
                 follow the rules for basic regular expressions described in
                 the Base Definitions volume of POSIX.1-2017, Section 9.3,
                 Basic Regular Expressions.  The application shall use the
                 sequence ""\\//"" to specify a <slash> character within the rexp.
                 The optional offset shall be a positive or negative integer
                 value representing a number of lines. A positive integer
                 value can be preceded by ''++''.  If the selection of lines from
                 an offset expression of this type would create a file with
                 zero lines, or one with greater than the number of lines left
                 in the input file, the results are unspecified. After the
                 section is created, the current line shall be set to the line
                 that results from the evaluation of the regular expression
                 with any offset applied. If the current line is the first
                 line in the file and a regular expression operation has not
                 yet been performed, the pattern match of rexp shall be
                 applied from the current line to the end of the file.
                 Otherwise, the pattern match of rexp shall be applied from
                 the line following the current line to the end of the file.

       %rexp%[[offset]]
                 Equivalent to /rexp/[[offset]], except that no file shall be
                 created for the selected section of the input file. The
                 application shall use the sequence ""\\%%"" to specify a
                 <percent-sign> character within the rexp.

       line__no   Create a file from the current line up to (but not including)
                 the line number line__no.  Lines in the file shall be numbered
                 starting at one. The current line becomes line__no.

       {num}     Repeat operand. This operand can follow any of the operands
                 described previously. If it follows a rexp type operand, that
                 operand shall be applied num more times. If it follows a
                 line__no operand, the file shall be split every line__no lines,
                 num times, from that point.

       An error shall be reported if an operand does not reference a line
       between the current position and the end of the file.

STDIN
       See the INPUT FILES section.

INPUT FILES
       The input file shall be a text file.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of
       csplit:

       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__COLLATE
                 Determine the locale for the behavior of ranges, equivalence
                 classes, and multi-character collating elements within
                 regular expressions.

       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) and the behavior of character classes within regular
                 expressions.

       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.

ASYNCHRONOUS EVENTS
       If the -k option is specified, created files shall be retained.
       Otherwise, the default action occurs.

STDOUT
       Unless the -s option is used, the standard output shall consist of one
       line per file created, with a format as follows:


           "%d\n", <file size in bytes>

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       The output files shall contain portions of the original input file;
       otherwise, unchanged.

EXTENDED DESCRIPTION
       None.

EXIT STATUS
       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.

CONSEQUENCES OF ERRORS
       By default, created files shall be removed if an error occurs. When the
       -k option is specified, created files shall not be removed if an error
       occurs.

       The following sections are informative.

APPLICATION USAGE
       None.

EXAMPLES
        1. This example creates four files, cobol00 ...  cobol03:


               csplit -f cobol file '/procedure division/' /par5./ /par16./

           After editing the split files, they can be recombined as follows:


               cat cobol0[0-3] > file

           Note that this example overwrites the original file.

        2. This example would split the file after the first 99 lines, and
           every 100 lines thereafter, up to 9999 lines; this is because lines
           in the file are numbered from 1 rather than zero, for historical
           reasons:


               csplit -k file  100  {99}

        3. Assuming that prog.c follows the C-language coding convention of
           ending routines with a ''}}'' at the beginning of the line, this
           example creates a file containing each separate C routine (up to
           21) in prog.c:


               csplit -k prog.c '%main(%'  '/^}/+1' {20}

RATIONALE
       The -n option was added to extend the range of filenames that could be
       handled.

       Consideration was given to adding a -a flag to use the alphabetic
       filename generation used by the historical split utility, but the
       functionality added by the -n option was deemed to make alphabetic
       naming unnecessary.

FUTURE DIRECTIONS
       None.

SEE ALSO
       sed, split

       The Base Definitions volume of POSIX.1-2017, Chapter _8, Environment
       Variables, Section 9.3, Basic Regular Expressions, Section 12.2,
       Utility Syntax Guidelines

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                            CSPLIT(1)
