.\" Copyright (c) 2002 Tim J. Robbins.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd December 24, 2008
.Dt CSPLIT 1
.Os
.Sh NAME
.Nm csplit
.Nd split files based on context
.Sh SYNOPSIS
.Nm
.Op Fl ks
.Op Fl f Ar prefix
.Op Fl n Ar number
.Ar file args ...
.Sh DESCRIPTION
The
.Nm
utility splits
.Ar file
into pieces using the patterns
.Ar args .
If
.Ar file
is
a dash
.Pq Sq Fl ,
.Nm
reads from standard input.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl f Ar prefix
Give created files names beginning with
.Ar prefix .
The default is
.Dq Pa xx .
.It Fl k
Do not remove output files.
.It Fl n Ar number
Use
.Ar number
of decimal digits after the
.Ar prefix
to form the file name.
The default is 2.
.It Fl s
Do not write the size of each output file to standard output as it is
created.
.El
.Pp
The
.Ar args
operands may be a combination of the following patterns:
.Bl -tag -width indent
.It Xo
.Sm off
.Cm / Ar regexp Cm / Op Oo Cm + | - Oc Ar offset
.Sm on
.Xc
Create a file containing the input from the current line to (but not including)
the next line matching the given basic regular expression.
An optional
.Ar offset
from the line that matched may be specified.
.It Xo
.Sm off
.Cm % Ar regexp Cm % Op Oo Cm + | - Oc Ar offset
.Sm on
.Xc
Same as above but a file is not created for the output.
.It Ar line_no
Create containing the input from the current line to (but not including)
the specified line number.
.It Cm { Ns Ar num Ns Cm }
Repeat the previous pattern the specified number of times.
If it follows a line number pattern, a new file will be created for each
.Ar line_no
lines,
.Ar num
times.
The first line of the file is line number 1 for historic reasons.
.El
.Pp
After all the patterns have been processed, the remaining input data
(if there is any) will be written to a new file.
.Pp
Requesting to split at a line before the current line number or past the
end of the file will result in an error.
.Sh ENVIRONMENT
The
.Ev LANG , LC_ALL , LC_COLLATE
and
.Ev LC_CTYPE
environment variables affect the execution of
.Nm
as described in
.Xr environ 7 .
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES
Split the
.Xr mdoc 7
file
.Pa foo.1
into one file for each section (up to 20):
.Pp
.Dl "csplit -k foo.1 '%^\e.Sh%' '/^\e.Sh/' '{20}'"
.Pp
Split standard input after the first 99 lines and every 100 lines thereafter:
.Pp
.Dl "csplit -k - 100 '{19}'"
.Sh SEE ALSO
.Xr sed 1 ,
.Xr split 1 ,
.Xr re_format 7
.Sh STANDARDS
The
.Nm
utility conforms to
.St -p1003.1-2001 .
.Sh HISTORY
A
.Nm
command appeared in PWB UNIX.
.Sh BUGS
Input lines are limited to
.Dv LINE_MAX
(2048) bytes in length.