Please wrap your code snippets within a
<code> </code> block. Also of possible interest to you;

Does your script contain:

use strict;
use warnings;
[download]

Please also see: How do I post a question effectively?, if you have any other questions regarding the proper format of a question. Or it's markup.

Best wishes.

--Chris

sorry for that, because i don't really what i supposed to do, very confusing now -_-

#!/usr/bin/perl -w
use warnings;
use strict;
use cwd;


our $input="";
our $web="";
our $help="";
our $version="";
our $path="";





foreach my $input(@ARGV){

if($input =~ m/\-d(.*)/) {
    $path=$1;
}

elsif($input =~ m/\-f(.*)/) {
    if($1 eq "h") {
    $web = "h";
    }
    elsif($1 eq "t") {
    $web = "t";
    }
} 

elsif($input =~ m/\-h/ ){
    $help = "h";
}

elsif($input =~ m/\-s(.*)/) {
    if($1 eq "a") {
    $web = "a";
    }
    elsif($1 eq "d") {
    $web = "d";
    }
    
} 

elsif($input =~ m/\-v/ ){
    $version = "v";
} }

#calling of methods
if($web eq "h") {
gethtml();
}

if($web eq "t") {
gettext();
}

if($help eq "h") {
gethelp();
}

if($version eq "v") {
getversion();
}

if($web eq "a") {
sortedasc();
}

if($web eq "d") {
sorteddesc();
}



#methods

sub gethtml{
    open(FH, ">plain.html");    
    print "sasasasas";
    close (FH);    
}

sub gettext{
    open(FH1, "/home/GUAN/Data/output.txt") or die "Error, no such fil
+e found";
    print <FH1>;
    close (FH1);
}

sub getdefault{
    open(FH1, "/home/GUAN/Data/output.txt") or die "Error, no such fil
+e found";
    print <FH1>;
    close (FH1);
}

sub sorteddesc{
    open(FH1, "/home/GUAN/Data/output.txt") or die "Error, no such fil
+e found";
    print sort{ $b cmp $a } <FH1>;
    close (FH1);
 }

sub sortedasc{
    open(FH1, "/home/GUAN/Data/output.txt") or die "Error, no such fil
+e found";
    print sort{ $a cmp $b } <FH1>;
    close (FH1);
}

sub gethelp {
print "Usage: {file name} [switches]
&#8208;dpath directory to search for html files (default: .)
&#8208;f[th] output in text or html mode (default: text)
&#8208;h print this message and exit
&#8208;s[adn] sort in ascending, descending or none (default: none)
&#8208;v print version and exit";
}

sub getversion {
print "***************************************************************
+********\n
ST2614 Assignment 1, Ver. 5.0 done by Guan Zhimin p1333114 class 2A/01
+\n
**********************************************************************
+*";
}

# sub lookfor {
# my $dir = '.';
# opendir(DIR, $dir) or die $!;
# while (my $file = readdir(DIR)) {
    # next if ($file =~ m/^\./);
    # print "$file\n";
    # }
    # closedir(DIR);
    # exit 0;

# }
[download]

A few tips :)

• there is no "cwd" module, case matters
• You've got subs, fantastic, now make them take parameters :) don't hardcode filenames
• speaking of filehandles, you can also use open my $foo, '<', ..., you don't have to use globals like FH1
• error checking is for everyone, even you can use autodie, or better still use Path::Tiny
• readdir is not for you, its like making your own stone/axe, when you already have swiss army chainsaw ... use Path::Tiny and/or File::Find::Rule; examples can be found with find/rule and path tiny links
• long if/else @ARGV option scan is busy work :) use perl -s or even better use Getopt::Long which allows you to use lexical variables not just globals
• you've got unicode text but you're not telling perl you're using unicode, or your console, see utf8.pm, binmode, open.pm perlunitut: Unicode in Perl#I/O flow (the actual 5 minute tutorial)
• naming is important, calling a subroutine "gethtml" when its purpose is to "sethtml" is too "clever"
• Basic debugging checklist and brian's Guide to Solving Any Perl Problem ) ... On debugging, verify everything, talk to teddybear ... checklists and more, Re^3: A Beginner Needs Homework help

so i think it is use Cwd; , not i don't want to use other modules, but my assignment only allows me to use that 3 modules. right now i having problem to make assignment1.pl -fh to be able to redirected into a file and view from the web browser.