.ds Vn 1.12
.TH vselect 1Vi "24 April 1993" "Vista Version \*(Vn"
.SH NAME
vselect \- select objects from a Vista data file
.SH SYNOPSIS
\fBvselect\fR [\fB-\fIoption\fR ...] [\fIinfile\fR] [\fIoutfile\fR]
.SH DESCRIPTION
\fBvselect\fP copies selected objects from an input file to an output file.
.PP
Command line options specify which objects are to be copied. Objects may be
selected by type (e.g., all images), by name, by the value of some 
attribute, or by position within the input file.
.SH "COMMAND LINE OPTIONS"
\fBvselect\fP accepts the following options:
.IP \fB-help\fP 15n
Prints a message describing options.
.IP \fB-in\fP
Specifies a Vista data file from which objects are to be selected.
.IP \fB-out\fP
Specifies where to write the selected objects as a Vista data file.
.PP
The input and output files can be specified on the command line or allowed to
default to the standard input and output streams.
.PP
In addition, exactly one of the following options must be used to specify 
the objects to be selected: 
.IP "\fB-object\fP \fIi\fP" 15n
Select the \fIi\fPth object. Objects in the input file are
numbered consecutively from 0.
.IP "\fB-name\fP \fIname\fP"
Select any object whose attribute name is \fIname\fP.
.IP "\fB-type\fP \fItype\fP"
Select any object whose type is \fItype\fP.
.IP "\fB-attr \fIname value\fP"
Select any object having an attribute with the specified name and value.
.PP
Finally, any of these selection criteria can be inverted:
.IP \fB-not\fP 15n
Reverses the sense of the selection criterion.
.SH EXAMPLES
To select the first object from a file:
.IP
.B "vselect -object 0 < infile > outfile"
.PP
To select the attribute named ``cantaloupe'' from a file:
.IP
.B "vselect -name cantaloupe < infile > outfile"
.PP
To select everything but images from a file:
.IP 
.B "vselect -type image -not < infile > outfile"
.PP
To select images with \fBubyte\fP pixels from a file of images:
.IP
.B "vselect -attr nbands ubyte < infile > outfile"
.SH AUTHOR
Art Pope <pope@cs.ubc.ca>