.\" Copyright (c) 2002 Tim J. Robbins.
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" $FreeBSD$
.\"
.Dd April 28, 2002
.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
.Bk
.Ar args ...
.Ek
.Sh DESCRIPTION
The
.Nm
utility splits
.Ar file
into pieces using the patterns
.Ar args... .
If
.Ar file
is
a dash
.Pq Ql \&- ,
.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
.Sq Pa xx .
.It Fl k
Do not remove output files if an error occurs or a
.Dv HUP ,
.Dv INT
or
.Dv TERM
signal is received.
.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 "line_no"
.It Cm / Ns Ar regexp Ns Cm / Ns Oo Oo +|- Oc Ns Ar offset Oc
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 Cm % Ns Ar regexp Ns Cm % Ns Oo Oo +|- Oc Ns Ar offset Oc
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
.Em line_no
lines,
.Em 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 EXAMPLES
Split the
.Xr mdoc 7
file
.Pa foo.1
into one file for each section (up to 20):
.Pp
.D1 Ic csplit -k foo.1 '%^\e.Sh%' '/^\e.Sh/' '{20}'
.Pp
Split standard input after the first 99 lines and every 100 lines thereafter:
.Pp
.D1 Ic csplit -k - 100 '{19}'
.Sh DIAGNOSTICS
.Ex -std
.Sh SEE ALSO
.Xr sed 1 ,
.Xr split 1 ,
.Xr re_format 7
.Sh STANDARDS
The
.Nm
utility conforms to
.St -p1003.1-2001 .