I am only a few days in and have only made a couple things from the book I have been going through, so go easy :P. I have tried searching online and have tried different ways but I can not seem to pass the MAC properly to system().
What I am trying to achieve is have perl open a .txt file of MAC's each MAC is on its own separate line. Then with it reading each line taking one MAC at a time and passing it system() as an arg so aircrack can be passed the MAC arg. I have it showing the MAC being read each line properly but I can not figure out why aircrack complains the MAC its being given is not a valid MAC. Is this due to me not chomping the line read?
What I have not tried as of yet due to this complication is I eventually want it to print a found key to a file if aircrack says it has found one, or if it does not find one moves on to the next BSSID, continuing until there are no more MACs in the file to try.
the MACs are in a txt file as so
00:00:00:00:00:00
00:00:00:00:00:00
00:00:00:00:00:00
and so on
#!/usr/bin/perl
use strict;
use warnings;
my $file = '/kismetLOGS/PcapDumpKismet/WEPMACS.txt';
open my $info, $file or die "Could not open $file: $!";
while( my $line = <$info>)
{
print $line;
system("/usr/local/bin/aircrack-ng", "-b $line", "*.pcap *.pcapdump");
last if $. == 0;
}
close $info;
exit;
Thanks for any help, tips and pointers. Not looking for a spoon feed :) And hopefully I posted properly for everyone and if I am way off in how I am trying this for my end goal please feel free to say and any tips about the correct route to try would be appreciated
You can either combine all your arguments together, like
system("/usr/local/bin/aircrack-ng -b $line *.pcap *.pcapdump");
or separate them all, like
system("/usr/local/bin/aircrack-ng", "-b","$line", "*.pcap","*.pcapdump");
The latter is usually safer, for spaces in the items not to need be escaped. But then globbing doesnt work, as the arguments are passed directly to the system for execution.
If you want *.pcap to work, you'll need to go with the first version.
$line ends with a newline character. You should remove the newline character.
chomp $line;
about last if $. == 0;,change it to last if $. ~~ 0 which infers the type of the variables when doing the comparison. Remove it if you want to iterate over all of the MAC addresses, as is it will only run on the first ( 0th ) line.
Related
I want to read a file by one line, but it's reading just the first line. How to read all lines?
My code:
open(file_E, $file_E);
while ( <file_E> ) {
/([^\n]*)/;
print $line1;
}
close($file_E);
Let's start by looking at your code.
open(file_E, $file_E);
while ( <file_E> ) {
/([^\n]*)/;
print $line1;
}
close($file_E);
On the first line you open a file named in $file_E using the bareword filehandle file_E. This should work so long as the file successfully opens. It would be better to also check the success of this operation one of two ways: Either put use autodie; at the top of your script (but then risk applying its semantics in places where your code is incompatible with this level of error handling), or change your open to look like this:
open(file_E, $file_E) or die "Failed to open $file_E: $!\n";
Now if you fail to open the file you will get an error message that will help track down the problem.
Next lets look at the while loop, because it's here where you have an issue that is causing the bug you are experiencing. On the first line of the while loop you have this:
while ( <file_E> ) {
By consulting perldoc perlsyn you will see that line is special-cased to actually do this:
while (defined($_ = <file_E>)) {
So your code is implicitly assigning each line to $_ on successive iterations. Also by consulting perldoc perlop you'll find that when the match operator (/.../ or m/.../) is invoked without binding the match explicitly using =~, the match will bind against $_. Still then, so far so good. However, you are not actually doing anything useful with the match. The match operator will return Boolean truth / falsehood for whether or not the match succeeded. And because your pattern contains capturing parenthesis, it will capture something into the capture variable $1. But you are never testing for match success, nor are you ever referring to $1 again.
On the line that follows, you do this: print $line1. Where, in your code, is $line1 being assigned a value? Because it is never being assigned a value in what you've shown us.
I can only guess that your intent is to iterate over the lines of the file, capture the line but without the trailing newline, and then print it. It seems that you wish to print it without any newlines, so that all of the input file is printed as a single line of output.
open my $input_fh_e, '<', $file_E or die "Failed to open $file_E: $!\n";
while(my $line = <$input_fh_e>) {
chomp $line;
print $line;
}
close $input_fh_e or die "Failed to close $file_E: $!\n";
No need to capture anything -- if all that the capture is doing is just grabbing everything up to the newline, you can simply strip off the newline with chomp to begin with.
In my example I used a lexical filehandle (a file handle that is lexically scoped, declared with my). This is generally a better practice in modern Perl as it avoids using a bareword, avoids possible namespace collisions, and assures that the handle will get closed as soon as the lexical scope closes.
I also used the 'three arg' version of open, which is safer because it eliminates the potential for $file_E to be used to open a pipe or do some other nefarious or simply unintended shell manipulation.
I suggest also starting your script with use strict;, because had you done so, you would have gotten an error message at compiletime telling you that $line1 was never declared. Also start your script with use warnings, so that you would get a warning when you try to print $line1 before assigning a value to it.
Most of the issues in your code will be discussed in perldoc perlintro, which you can arrive at from your command line simply by typing perldoc perlintro, assuming you have Perl installed. It typically takes 20-40 minutes to read through perlintro. If ever there were a document that should constitute required reading before getting started writing Perl code, that reading would probably include perlintro.
Another alternative, note that $_ will include newline so you will need to chomp it if you don't want the newline in $line:
open(file_E, $file_E);
while ( <file_E> ) {
my $line = $_;
print $line;
}
close($file_E);
I have a Perl script that I, well, mostly pieced together from questions on this site. I've read the documentation on some parts to better understand it. Anyway, here it is:
#!/usr/bin/perl
use File::Find;
my $dir = '/home/jdoe';
my $string = "hard-coded pattern to match";
find(\&printFile, $dir);
sub printFile
{
my $element = $_;
if(-f $element && $element =~ /\.txt$/)
{
open my $in, "<", $element or die $!;
while(<$in>)
{
if (/\Q$string\E/)
{
print "$File::Find::name\n";
last; # stops looking after match is found
}
}
}
}
This is a simple script that, similar to grep, will look down recursively through directories for a matching string. It will then print the location of the file that contains the string. It works, but only if the file is located in my home directory. If I change the hard-coded search to look in a different directory (that I have permissions in), for example /admin/programs, the script no longer seems to do anything: No output is displayed, even when I know it should be matching at least one file (tested by making a file in admin/programs with the hard-coded pattern. Why am I experiencing this behavior?
Also, might as well disclaim that this isn't a really useful script (heck, this would be so easy with grep or awk!), but understanding how to do this in Perl is important to me right now. Thanks
EDIT: Found the problem. A simple oversight in that the files in the directory I was looking for did not have .txt as extension. Thanks for helping me find that.
I was able to get the desired output using the code you pasted by making few changes like:
use strict;
use warnings;
You should always use them as they notify of various errors in your code which you may not get hold of.
Next I changed the line :
my $dir = './home/jdoe'; ##'./admin/programs'
The . signifies current directory. Also if you face problems still try using the absolute path(from source) instead of relative path. Do let me know if this solves your problem.
This script works fine without any issue. One thing hidden from this script to us is the pattern. you can share the pattern and let us know what you are expecting from that pattern, so that we can validate that.
You could also run your program in debug mode i.e.,
perl -d your_program.
That should take you to debug mode and there are lot of options available to inspect through the flow. type 'n' on the debug prompt to step in to the code flow to understand how your code flows. Typing 'n' will print the code execution point and its result
I'm a self-taught Perler, seeking assistance from the Perl experts:
I keep getting an error saying I can't use the filehandle within a foreach loop, even though I'm sure to close it (or undef it, I've tried both). See the full error here: http://cl.ly/image/2b2D1T403s14
The code is available on GitHub: https://github.com/bsima/yeast-TRX
The code in question can be found in the file "script.pl" at around line 90:
foreach my $species (keys %Saccharomyces) {
open(RAW,">./data/$species/$geneName/raw.csv");
print RAW "gene,dinucleotide,position,trx.score,energy.score\n";
undef RAW;
open(SMOOTH,">./data/$species/$geneName/smooth.csv");
print SMOOTH "gene,position,trx.score,energy.score\n";
undef SMOOTH;
}
Help is much appreciated! I don't know the intricacies of how Perl works with filehandles, probably because of my lack of formal training. Any comments on my overall code quality is welcome too, if someone is feeling particularly helpful.
EDIT: Found the problem. Perl cannot generate directories on the fly, so the $species/$geneName directory was never even being created. I added a line at the beginning of the foreach loop that said simply mkdir("$species/$geneName"); and that solve the issue.
You are getting warning that is quite telling:
Bareword RAW not allowed while "strict subs" in use
Also, undef FILEHANDLE is not as good as close FILEHANDLE.
Solution is to use normal scoped variables for file handles and close them, something like this:
foreach my $species (keys %Saccharomyces) {
open my $raw, ">", "./data/$species/$geneName/raw.csv";
print $raw "gene,dinucleotide,position,trx.score,energy.score\n";
close $raw;
open my $smooth, ">", "./data/$species/$geneName/smooth.csv";
print $smooth "gene,position,trx.score,energy.score\n";
close $smooth;
}
Also, you should check if $raw and $smooth were opened before trying to write to them.
Perl cannot generate directories on the fly, so the $species/$geneName directory was never even being created. I added a line at the beginning of the foreach loop that said simply mkdir("$species/$geneName"); and that solve the issue.
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I am working on a program that takes information from a CSV file as a source to search with through a text file that has "customer packages". I am getting odd counts on only some of the entries, and I can't seem to figure out what is causing the duplicate counts. Can anyone look through my code and tell me if my logic/syntax is off? (probably is). All i am trying to accomplish is to count the total occurances in the text file of an entry in the csv file (packageid,package_description)
Thanks for the help! im going nuts over here.
#!/usr/bin/perl
use strict;
use Text::CSV;
# Variables already declared in the other PL file ** Remove if consolidating **
my $file2 = 'master_plist.csv';
my $csv2 = Text::CSV->new(); # Create a Text::CSV object
open (CSV2, "<", $file2) or die $!; #open CSV file for parsing
while (<CSV2>) {
if ($csv2->parse($_)) {
my #columns2 = $csv2->fields(); # Parse CSV and load into an array for each row.
my $packID = $columns2[0];
my $packDESC = $columns2[1];
my $val = 'customer_packages_report.txt';
chomp ($val);
my $cnt=0;
open (HNDL, "$val") || die "wrong filename";
while ($val = <HNDL>)
{
while ($val =~ /$packID - $packDESC/ig)
{
$cnt++;
}
}
#if ($packDESC =~ /\(/g) {
# $packDESC =~ s/\(/\(/g;
#}
print "Total iterations of $packDESC: $cnt\n";
close (HNDL);
# End original code
} # Close IF
} # Close WHILE
close CSV;
#!/usr/bin/perl
use strict;
use warnings;
use Text::CSV;
# Variables already declared in the other PL file ** Remove if consolidating **
my $file2 = 'master_plist.csv';
my $csv2 = Text::CSV->new(); # Create a Text::CSV object
open (CSV2, "<", $file2) or die "I die while opening $file2! $!"; #open CSV file for parsing
while ($each_csv2_line=<CSV2>) {
if ($csv2->parse($each_csv2_line)) {
my #columns2 = $csv2->fields(); # Parse CSV and load into an array for each row.
my $packID = $columns2[0];
my $packDESC = $columns2[1];
my $val = 'customer_packages_report.txt';
chomp ($val);
my $cnt=0;
open (HNDL,"<","$val") or die "wrong filename: $val! $!";
while (<HNDL>){
$cnt++ while (/$packID - $packDESC/ig);
}
#if ($packDESC =~ /\(/g) {
# $packDESC =~ s/\(/\(/g;
#}
print "Total iterations of $packDESC: $cnt\n";
close (HNDL);
# End original code
} # Close IF
} # Close WHILE
# end of script
close CSV;
My recommendations:
Use $HNDL instead of HNDL <- lexical variables for filehandles more better.
Try to catch all mistakes (by defined and ==0 and eq "")
I try to format your code and add some features that i sometimes use. Be better than me and read first Style Coding for Little Perl Monk. And you can be more impressive with this language and write not only writeonly code.
Example (and also a quote):
"The situation is exactly the same for the line-input operator, <>, although Perl does this for you automatically.
It looks like you’re testing the line from STDIN in this while:
while (<STDIN>) {
do_something($_);
}
However, this is a special case in which Perl automatically converts to check $_ for definedness:
while ( defined( $_ = <STDIN> ) ) { # implicitly done
do_something($_);
}
"
Effective Perl Programming, page 24.
You could do a number of things to improve your code:
use warnings;.
Use proper indentation.
Use descriptive variable names. Instead of $file2 (has no meaning, and why is there no file 1?), use $package_file or whatever makes sense.
if you are already using Text::CSV, you can use $csv->getline() to go through the file line by line. This will simplify your code. See the documentation for an example.
chomp($val) removes a newline from the end of a string. You are using it on a string literal you just declared, which has no newline. That doesn't make sense.
Never use the same variable ($val) to do two completely different things. This is extremely confusing.
Might the variables that you are interpolating in the regex contain special characters? If so, you need to escape them. For example, if $packDESC contained a period, it would match any character in the regex. To treat the contents of the variable literally, use \Q..\E, as in this example: /\Q$packID - $packDESC\E/ig.
You are opening customer_packages_report.txt and going through it line-by-line on every line of the csv file. You could simplify this by reading it in once and storing the results in an array.
You don't need a while loop to count matches: $cnt = () = /$packID - $packDESC/ig;. This puts the match in array context, returning an array of matches, then puts it back in scalar context to count the matches. A little bit tricky, but simpler.
It's hard to say exactly what is causing your problem without seeing the data. Might you have some unnecessary repetition that stems from your nested looping over both files? I would start by rewriting to improve your code, then see if the problem still exists.
Your code seems to compile with perl -c without errors, so that's good. If I were to guess, I would assume your problem lies in having meta characters in some of your fields. The regex /$packID - $packDESC/ is vulnerable to meta characters. For example
my $str = "foo? bar";
$str =~ /$str/; # returns false, because ? is a meta character
In the above example, the question mark ? is a quantifier which affects whatever comes before it, so that o? means "0 or 1 o". To solve the meta character problem, use the \Q ... \E escape:
$str =~ /\Q$str/; # will now match
Terminating the escape sequence with \E is optional.
Some other things to note:
It is very good that you use use strict. You should also always use warnings. Not doing so is not removing the issues with your code, only hiding them.
You create a Text::CSV object with default settings. Depending on your input, that may or may not be appropriate. Setting binary => 1 is recommended in the documentation.
Using the parse() function may not be the best option, the documentation has good things to say about getline.
As loldop points out in the comments, you are reusing $val to read from your file. While technically that should work, it is asking for trouble.
Style and practice notes and practical tips:
Using three-argument open and lexical file handles is a good thing to do. Three-argument in essence means to use an explicit open mode, which makes your script safer to use. Using lexical file handles means that you will not have global scope on your file handle, which is a good thing.
This code
my #columns2 = $csv2->fields();
my $packID = $columns2[0];
my $packDESC = $columns2[1];
Can be written like this
my ($packID, $packDESC) = $csv2->fields();
You are chomping $val right after you assign it. That is redundant, because chomp by default only removes newlines from the end of your strings, and you did not add any such. It doesn't change anything, but not required here. If you read something from stdin or a file, you would probably want to use chomp, though.
Using die without referring to the error $! is a sure way to make yourself annoyed.
Do not underestimate how much easier it becomes to write code when you use proper indentation. Use a text editor with automatic indentation and colouring. I can warmly recommend vim (gvim if you are using windows). Though it has a learning curve, is is a powerful editor that also often comes already installed on many systems.
Since so many people have already commented on your program itself, I'm going to talk about how you can become a better Perl programmer, and help write in such a way that will help eliminate many of your issues.
Take a look at Perl::Tidy and run your program thorough that. That will help improve your syntax and Perl and will help you catch a lot of the various issues you're having.
Also, you should get a copy of Perl Best Practices which is where most of Perl Tidy is taken from. And, as someone already referenced Effective Perl Programming is another excellent book.
The big issue with Perl is that few people learn it. Most are tossed into a situation where we had to pick it up ourselves. Plus, Perl is a fairly old and rather crufty language. Most Perl books still lean heavily on Perl 3.x ways of programming and fail to mention such basics as using use strict; and use warnings;.
You combine old programming practices, with most people learning Perl by hacking their way through old programs with old syntax (and probably written by people who learned Perl by hacking their way through even older programs), and you can see why Perl has a reputation of being a write-only language.
You may want to use the getline method from Text::CSV, which saves a few lines of code.
The problem is likely to be because you have regex metacharacters in the strings you are searching for. Escape them with \Q...\E in the regex so that they are taken literally. In the rewrite below I have also added \s* instead of a literal space, just in case there isn't exactly one space on either side of the hyphen.
I have also changed the filehandles to lexical ones, which have the advantage that they will be closed automatically when the handle goes out of scope.
#!/usr/bin/perl
use strict;
use warnings;
use Text::CSV;
my $file2 = 'master_plist.csv';
my $csv2 = Text::CSV->new();
open(my $csv_fh, '<', $file2) or die $!;
while (my $row = $csv2->getline($csv_fh)) {
my ($packID, $packDESC) = #$row;
my $val = 'customer_packages_report.txt';
chomp($val);
open(my $fh, '<', $val) or die "wrong filename";
my $cnt = 0;
while ($val = <$fh>) {
while ($val =~ /\Q$packID\E\s*-\s*\Q$packDESC\E/ig) {
$cnt++;
}
}
print "Total iterations of $packDESC: $cnt\n";
}
I have a Perl script which reads three files and writes new files after reading each one of them. Everything is one thread.
In this script, I open and work with three text files and store the contents in a hash. The files are large (close to 3 MB).
I am using a loop to go through each of the files (open -> read -> Do some action (hash table) -> close)
I am noticing that the whenever I am scanning through the first file, the Perl terminal window in my Cygwin shell gets stuck. The moment I hit the enter key I can see the script process the rest of the files without any issues.
It's very odd as there is no read from STDIN in my script. Moreover, the same logic applies to all the three files as everything is in the same loop.
Has anyone here faced a similar issue? Does this usually happen when dealing with large files or big hashes?
I can't post the script here, but there is not much in it to post anyway.
Could this just be a problem in my Cygwin shell?
If this problem does not go away, how can I circumvent it? Like providing the enter input when the script is in progress? More importantly, how can I debug such a problem?
sub read_set
{
#lines_in_set = ();
push #lines_in_set , $_[0];
while (<INPUT_FILE>)
{ $line = $_;
chomp($line);
if ($line=~ /ENDNEWTYPE/i or $line =~ /ENDSYNTYPE/ or eof())
{
push #lines_in_set , $line;
last;
}
else
{
push #lines_in_set , $line;
}
}
return #lines_in_set;
}
--------> I think i found the problem :- or eof() call was ensuring that the script would be stuck !! Somehow happening only at the first time. I have no idea why though
The eof() call is the problem. See perldoc -f eof.
eof with empty parentheses refers to the pseudo file accessed via while (<>), which consists of either all the files named in #ARGV, or to STDIN if there are none.
And in particular:
Note that this function actually reads a character and then "ungetc"s it, so isn't useful in an interactive context.
But your loop reads from another handle, one called INPUT_FILE.
It would make more sense to call eof(INPUT_FILE). But even that probably isn't necessary; your outer loop will terminate when it reaches the end of INPUT_FILE.
Some more suggestions, not related to the symptoms you're seeing:
Add
use strict;
use warnings;
near the top of your script, and correct any error messages this produces (perl -cw script-name does a compile-only check). You'll need to declare your variables using my (perldoc -f my). And use consistent indentation; I recommend the same style you'll find in most Perl documentation.