How can I process options using Perl in -n or -p mode?

by

There are three primary ways of passing information to Perl without using STDIN or external storage.

  • Arguments

    When using -n or -p, extract the arguments in the BEGIN block.

      perl -ne'BEGIN { ($x,$y)=splice(@ARGV,0,2) } f($x,$y)' -- "$x" "$y" ...

  • Command-line options

    In a full program, you’d use Getopt::Long, but perl -s will do fine here.

      perl -sne'f($x,$y)' -- -x="$x" -y="$y" -- ...

  • Environment variables

      X="$x" Y="$y" perl -ne'f($ENV{X},$ENV{Y})' -- ...

More Related Contents:

  1. How can i do this in perl, shortcut truthtable [closed]
  2. How to retrieve the values of required keys in Perl [closed]
  3. Perl: Meaning of double squared brackets after a string?
  4. What does this HTML::Parser() code do in Perl? [closed]
  5. Why use strict and warnings?
  6. Why does modern Perl avoid UTF-8 by default?
  7. Why is three-argument open calls with autovivified filehandles a Perl best practice?
  8. What’s the difference between Perl’s backticks, system, and exec?
  9. How can I parse dates and convert time zones in Perl?
  10. Which one is good practice, a lexical filehandle or a typeglob?
  11. How do I tell if a variable has a numeric value in Perl?
  12. Using perl’s `system`
  13. What’s the best way to open and read a file in Perl?
  14. How do I daemonize an arbitrary script in unix?
  15. How can I compile my Perl script so it can be executed on systems without ‘perl’ installed?
  16. How can I store the result of a system command in a Perl variable?
  17. How can I check if a file exists in Perl?
  18. How can I guess the encoding of a string in Perl?
  19. Using Encode::encode with “utf8”
  20. Using output from a previous job in a new one in a GitHub Action
  21. How can I start an interactive console for Perl?
  22. What does =~ do in Perl? [closed]
  23. Using my with parentheses and only one variable
  24. How to convert letters with accents, umlauts, etc to their ASCII counterparts in Perl?
  25. How can I extract text from a PDF file in Perl?
  26. Local and Global variables in perl
  27. What do you get if you evaluate a hash in scalar context?
  28. How do I retrieve the terminal width in Perl?
  29. How to make DateTime::Duration output only in days?
  30. How do I tell CPAN to install all dependencies?

Leave a Comment