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basic-unix-17.txt / txt

  Chapter 17
  #!/usr/bin/perl -w
  # Classic “Hello World” as done with Perl
  print “Hello World!\n”;
  #!/usr/bin/perl -w
  # Create a file that will have a directory listing of user’s home dir
  print “About to read user’s home directory\n”;
  # open the home directory and read it
  opendir(HOMEDIR, “.”);
  @ls = readdir HOMEDIR;
  print “About to create file dirlist.txt with a directory listing of user’s
  home dir\n”;
  # open a file and write the directory listing to the file
  open(FILE, “>dirlist.txt”);
  foreach item (@ls) {
  print FILE item .”\n”;
  print “All done\n\n”;
  # Global variable name is given a name
  name = Paul
  # Enter our loop
  foreach (@filedata) {
  # declare a new variable for just the loop
  my current_file_file;
  # create a local version of name to temporarily assign values within the
  # loop to
  local name
  while ( counter < 10 ) {
  print counter . “\n”;
  do {
  print counter . “\n”;
  } while ( counter < 10);
  foreach temp (@authors) {
  print temp . “\n”;
  if ( name eq ‘Paul’ ) {
  print “Hi Paul\n”;
  } elsif (name eq ‘Joe’) (
  print “Hi Joe\n”;
  } elsif (name eq ‘Jeremy’) {
  print “Hi Jeremy\n”;
  } else {
  print “Sorry, have we meet before? “;
  #!/usr/bin/perl -T
  # A Perl script that checks the input to determine if
  # it contains numeric information
  # First set up your Perl environment and import some useful Perl packages
  use warnings;
  use diagnostics;
  use strict;
  my result;
  # Next check for any input and then call the proper subroutine
  # based on the test
  if (@ARGV) {
  # If the test condition for data from standard in is true run
  # the test subroutine on the input data
  result = &test;
  } else {
  # else the test condition is false and you should run an error routine.
  # Now print the results
  print ARGV[0].” has “.result.” elements\n\n”;
  exit (0);
  sub test {
  # Get the first array element from the global array ARVG
  # assign it to a local scalar and then test the local variable
  # with a regular expression
  my cmd_arg = ARGV[0];
  if(cmd_arg =~ m/[0-9]/) {
  return (‘numeric’);
  } else {
  # There was a error in the input; generate an error message
  warn “Unknown input”;
  sub error {
  # There was no input; generate an error message and quit
  die “Usage:, (<INPUT TO CHECK>)”;

(C) Æliens 20/2/2008

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