fields: Extract specified fields from a list

Package: proto

Usage

fields files fields

Parameters

files: File or files from which the fields are to be extracted.

fields: The fields to be extracted.

lines = "1-": The lines from which the fields are to be extracted. If multiple files are being extracted, the same lines apply to each file.

quit_if_missing = no: This flag determines the task behavior when a field is missing from the specified line. If quit_if_missing = yes, the task exits and an error is reported.

print_file_names = no: If print_file_name = yes, the first string of each output line of extracted fields is the file name.

Description

The list processing tool fields is used to extract whitespace separated fields from the specified files and lines. The input to this task can be either the standard input or a list of files; output is a new list of the extracted fields.

The fields of a line are numbered from 1 up to a newline character; those fields to be extracted are specified as a range of numbers. If a specified field is missing from a selected line the action taken is determined by the quit_if_missing flag; fields will either continue processing after printing a warning message, or call an error and exit.

Examples

1. Reverse the order of the 5 columns in list file "list".

cl> fields list 5-1 > newlist

2. Extract columns 1 and 3 from file "newlist" and pipe them to task graph.

cl> fields newlist 1,3 | graph

Revisions

FIELDS V2.11: The default value for the lines parameter was changed to an open upper limit.