.TH EXTRACT_METADATA 1 "01 February 2019"
.SH NAME
extract_metadata \- read column metadata from SPSS and Stata binary files, and format it as JSON
.SH SYNOPSIS
.B extract_metadata
.IR input-file
.IR output-file
.SH DESCRIPTION
.B extract_metadata
reads column metadata from existing binary data files, so that \fBreadstat\fR
can produce new, column-compatible binary files from CSV input files. Both programs
use JSON as a metadata interchange format.
.PP
The
.IR input\-file
should be a file with one of the following extensions:
.TP
.IR dta
Stata binary file, version 104 or newer
.TP
.IR sav
SPSS uncompressed binary file
.TP
.IR zsav
SPSS compressed binary file
.PP
In all cases, \fIoutput-file\fR should end in .json.
.SH EXAMPLE
Suppose you have a Stata file with last year's survey data, and want to produce
a compatible Stata file containing this year's survey data. First, extract the
metadata:
.PP
.nf
.RS
extract_metadata last-year.dta survey-metadata.json
.RE
.fi
.PP
Now apply it to this year's data, which is stored in a CSV file:
.PP
.nf
.RS
readstat this-year.csv metadata.json this-year.dta
.RE
.fi
.PP
The first line of the CSV file should contain column names which match the
column names in last-year.dta. If everything went well, your new binary data
set is now stored in this-year.dta.
.SH OPTIONS
.PP
None.
.SH AUTHOR
Copyright (C) 2012-2019 Evan Miller, and others where indicated.