ndselect - select lines and fields for numdiff
Usage: ndselect -h|--help|-v|--version or
ndselect [-b N][-e N][-s N][-F N][-L N][-I N][-S IFS][-D
    DELIMS][-O OSEP][-x][-l PATH][-o PATH] [FILE]
Print to standard output a subset of lines and fields from a given
    file.
The argument after the options is the name of the file to read
    from. The complete path of the file should be given, a directory name is not
    accepted. If no input file is specified, the program reads from the standard
    input.
Exit status: 0 in case of normal termination, -1 (255) in
    case of error
-b, --beginning, --start=N
  
  - Set to N the number of the first line to print (The default behavior is to
      start with line number 1)
 
-e, --end=N
  
  - Set to N the number of the last line that can be printed (The default
      behavior is to arrive till to the end of the file)
 
-s, --step=N
  
  - Set to N the increment to use when selecting the lines to print (The
      default value for the increment is 1)
 
-F, --first-field=N
  
  - Set to N the number of the first field to print (The default behavior is
      to start with field number 1)
 
-L, --last-field=N
  
  - Set to N the number of the last field that can be printed (The default
      behavior is to arrive till to the end of every line)
 
-I, --increment=N
  
  - Set to N the increment to use when selecting the fields to print (The
      default value for the increment is 1)
 
-S, --separators=IFS
  
  - Specify the set of characters to use as delimiters while splitting the
      input lines into fields (The default set of delimiters is space, tab and
      newline)
 
-D, --delimiters=DELIMS
  
  - Specify the set of strings to use as delimiters while splitting the input
      lines into fields (The default set of delimiters is space, tab and
      newline)
 
-O, --output-separator=OSEP
  
  - Specify the string to use as separator while writing the selected fields
      to the standard output (The default behavior consists in reusing
 
  
  - the delimiters found in the input lines)
 
-x, --omit-empty-lines
  
  - Do not print empty lines
 
-l, --warnings-to=PATH
  
  - Redirect warning and error messages from stderr to the indicated file
 
-o, --output=PATH
  
  - Redirect output from stdout to the indicated file
 
-h, --help
  
  - Show this help message
 
-v, --version
  
  - Show version number, Copyright, Distribution Terms and NO-Warranty
 
Copyright © 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012,
    2013, 2014, 2015, 2016, 2017 Ivano Primi <ivprimi@libero.it> License
    GPLv3+: GNU GPL version 3 or later, see
    <http://gnu.org/licenses/gpl.html>.
  
  This is free software: you are free to change and redistribute it. There is NO
    WARRANTY, to the extent permitted by law.
The full documentation for ndselect is maintained as a
    Texinfo manual. If the info and ndselect programs are properly
    installed at your site, the command
  
  - info numdiff
 
should give you access to the complete manual.