2.2 File Options

There are some attributes that apply to any file. They include such things as the way to tell one record from another, the way to identify fields within a record, and the fields in a file that you want to write out.

‘-d string’

‘--output-field-delimiter=string’

Print string between each pair of fields written to output files. This can be a comma, a tab character, your mother’s maiden name, or the full text of the GNU General Public License. It is your choice. Of course, it is most useful for it to be something that would not normally occur in your data fields and something that your target system will understand. Because combine doesn’t care about such things, you can even use the null character (\0) or the newline character (\n).

‘--no-output-field-delimiter’

This means that there is to be no delimiter between fields in the output file or files. It will prevent the input field delimiter from being taken as the output field delimiter. In cases like this, it might behoove you either to ensure that the fields have a fixed length or to use Guile to insert your own delimiters before they are written. When specified along with ‘--output-field-delimiter’, the option that appears later will override the prior one.

‘-b string’

‘--output-record-delimiter=string’

Similarly here string is whatever string you need to use to tell the records apart in output files. If you don’t specify it, combine will assume that the usual text format applies, the newline on GNU operating systems. (As of this writing, no port has been made to systems where a newline is not the standard end-of-line character.)

‘-D string’

‘--input-field-delimiter=string’

Look for string in the associated input file to determine where fields start and end. It can be any string, but it should be the string that really separates fields in your file. Because combine doesn’t care about such things, you can even use the null character (\0) or the newline character (\n). At present, there is no interpretation of quoted strings. As a result, you may get unexpected results if the delimiter shows up in the middle of one of your fields.

When specified for the data file, the value specified is used as the input field delimiter for all reference files and as the output field delimiter for any output files, unless other action is taken. The options ‘--no-input-field-delimiter’ and ‘--no-output-field-delimiter’ will tell combine that a given file should not have a delimiter. The options ‘--input-field-delimiter’ and ‘--output-field-delimiter’ will use whatever delimiter you specify rather than the data file input field delimiter.

‘--no-input-field-delimiter’

This means that there is no delimiter between fields in the specified input file or files. It will prevent the data file input field delimiter from being taken as the input field delimiter for a reference file. When specified along with ‘--output-field-delimiter’, the option that appears later will override the prior one.

‘-B string’

‘--input-record-delimiter=string’

Similarly here string is whatever string you need to use to tell the records apart in input files. If you don’t specify it, combine will assume that the usual text format applies, the newline on GNU operating systems.

‘-L number’

‘--input-record-length=number’

If the records are all of the same length (whether of not there is a linefeed or a ‘W’ between them), you can specify a record length. combine will then split the file into records all of exactly NUMBER bytes long. If there are linefeeds or carriage returns between records, be sure to add them to the count. If the length is not specified, combine will assume the records have a delimiter between them.

‘-p’

‘--match-optional’

Make it unnecessary to find a match to this file for inclusion in data file based output and for the further processing of a data record. All matches are required by default.

When applied to a reference file, this means that records based on a data record may be written without a match to a key in this reference file, and any output from fields in this file will be left blank (or substituted if specified with the ‘-O’ option).

When applied to a data file, this means that in the file based on the data file records, records will be written at the end of processing for reference file records that were not matched by a data file record. Any output specified from fields in the data file will be left blank (or substituted if specified with the ‘-O’ option). If there is more than one reference file, care should be taken, because the unmatched records from each reference file will each become a record in the output file. This has no effect on reference-file-based output.

‘-P’

‘--exclude-match’

Require no match to this file for inclusion in data file based output and for the further processing of a data record. All matches are required and included by default. This differs from ‘--match-optional’ in that records that do have a match are excluded from further consideration.

When applied to a reference file, this means that records based on a data record may only be written when there is no match to a key in this reference file, and any output from fields in this file will be left blank (or substituted if specified with the ‘-O’ option).

When applied to a data file, this means that in the file based on the data file records, records will only be written at the end of processing for reference file records that were not matched by a data file record. Any output specified from fields in the data file will be left blank (or substituted if specified with the ‘-O’ option). If there is more than one reference file, care should be taken, because the unmatched records from each reference file will each become a record in the output file. This has no effect on reference-file-based output.

This document was generated by Daniel P. Valentine on July 28, 2013 using texi2html 1.82.