Trying to troubleshoot a port of some perl code from CentOS to Windows.
Really know nothing about Perl, and the code I'm porting is around 700-1000 lines. 100% sure one of the issues I'm seeing is related to how the code is being rendered as a result of being on the OS it's running on.
So, I'm looking for a way to troubleshoot debugging how the OS's are rendering filepath apart from the legacy code; which I can not post to SO due to "IP" reasons.
So, I looking for some perl that I can set a directory to open within the script (for example, C:\data\ or /home/data), then script attempts to load the directory, prints if it failed or succeeded, and then prints the string it attempted to load, regardless if the code failed to open the directory or not.
Open to suggestions, but that's the issue, and the solution I'm seeing.
Questions, feedback, requests - just comment, thanks!!
use IO::Dir;
my $dir = IO::Dir->new($dir_path) or
die "Could not open directory $dir_path: $!\n";
of course, where $dir_path is some path to a directory on your system that you want, either as a var or hard coded. The more 'old school' way would look like:
opendir my $dir, $dir_path or die "Could not open directory $dir_path: $!\n";
That won't print of the directory is opened, but the program will fail if it doesn't open it then print the precise error as to why, which is what the $! variable holds.
Is this what you're looking for?
use DirHandle;
my $dir = "test";
my $dh = new DirHandle($dir);
if($dh) {
print "open directory succeeded\n";
}
else {
print "open directory failed\n";
}
print $dir, "\n";
new DirHandle opens the directory and returns a handle to it. The handle will be undef if the open failed.
Related
I am working on a script which utilizes files in surrounding directories using a path such as
"./dir/file.txt"
This works fine, as long as the working directory is the one containing the script. However the script is going out to multiple users and some people may not change their working directory and run the script by typing its entire path like this:
./path/to/script/my_script.pl
This poses a problem as when the script tries to access ./dir/file.txt it is looking for the /dir directory in the home directory, and of course, it can't fine it.
I am trying to utilize readdir and chdir to correct the directory if it isn't the right one, here is what I have so far:
my $working_directory = $ENV{PWD};
print "Working directory: $working_directory\n"; #accurately prints working directory
my #directory = readdir $working_directory; #crashes script
if (!("my_script.pl" ~~ #directory)){ #if my_script.pl isnt in #directoryies, do this
print "Adjusting directory so I work\n";
print "Your old directory: $ENV{PWD}\n";
chdir $ENV{HOME}; #make the directory home
chdir "./path/to/script/my_script.pl"; #make the directory correct
print "Your new directory: $ENV{PWD}\n";
}
The line containing readdir crashes my script with the following error
Bad symbol for dirhandle at ./path/to/script/my_script.pl line 250.
which I find very strange because I am running this from the home directory which prints out properly right beforehand and contains nothing to do with the "bad symbol"
I'm open to any solutions
Thank you in advance
The readdir operates with a directory handle, not a path on a string. You need to do something like:
opendir(my $dh, $working_directory) || die "can't opendir: $!";
my #directory = readdir($dh);
Check perldoc for both readdir and opendir.
I think you're going about this the wrong way. If you're looking for a file that's travelling with your script, then what you probably should consider is the FindBin module - that lets you figure out the path to your script, for use in path links.
So e.g.
use FindBin;
my $script_path = $FindBin::Bin;
open ( my $input, '<', "$script_path/dir/file.txt" ) or warn $!;
That way you don't have to faff about with chdir and readdir etc.
Although I found many posts on how to open a file in a for loop in perl, I am having a specific issue in creating a file within a directory ( which is also the array variable)-
I am opening a file using
foreach my $dir (#listofdirs) {
open (my $OUTFILE, '>', "$dir/$dir.txt") or die "$!";
, this does not create a file and gives me an error No such file or directory.
If i just use open (my $OUTFILE, '>', "$dir.txt") or die; It works and creates a file under main directory from where I execute the script.
How can I control/specify the path so that it opens a file inside each $dir variable (directory)? I am sorry if this has been addressed earlier, but I am not sure what is the right way to specify the path for the new files.
Edit -
Can I change directory where the file is being created inside the loop and assign it the $dir variable value everytime?
Without seeing your error message, I have a pretty good idea what's wrong.
foreach my $dir (#listofdirs) {
open (my $OUTFILE, '>', "$dir/$dir.txt") or die;
...
}
I'm going to guess #listofdirs contains things like /foo/bar or foo/bar/baz/ and thus "$dir/$dir.txt" will create some funny filepaths.
$dir "$dir/$dir.txt"
/foo/bar /foo/bar//foo/bar.txt
foo/bar/ foo/bar//foo/bar/.txt
foo/ foo//foo/.txt
Most of these aren't going to work for various reasons. /foo/bar//foo/bar.txt will require that the directory /foo/bar/foo/ already exists. foo/bar//foo/bar/.txt is an invalid path.
"$dir/$dir.txt" is a funny construct anyway. Are you sure that's what you meant to do?
To figure out what's gone wrong you can add an some information to your error message. The traditional way is to write it all out long hand on every open call.
foreach my $dir (#listofdirs) {
open (my $OUTFILE, '>', "$dir/$dir.txt")
or die "Can't open '$dir/$dir.txt': $!";
...
}
Now you'll see what it tried to open, and why it failed (contained in $!). This rapidly gets tiresome and inconsistent, so it's better to let autodie do it for you.
# at the top of your code along with things like "use strict"
use autodie;
...
foreach my $dir (#listofdirs) {
open (my $OUTFILE, '>', "$dir/$dir.txt");
...
}
I am trying to chdir in perl but I am just not able to get my head around what's going wrong.
This code works.
chdir('C:\Users\Server\Desktop')
But when trying to get the user's input, it doesn't work. I even tried using chomp to remove any spaces that might come.
print "Please enter the directory\n";
$p=<STDIN>;
chdir ('$p') or die "sorry";
system("dir");
Also could someone please explain how I could use the system command in this same situation and how it differs from chdir.
The final aim is to access two folders, check for files that are named the same (eg: if both the folders have a file named "water") and copy the file that has the same name into a third folder.
chdir('$p') tries to change to a directory literally named $p. Drop the single quotes:
chdir($p)
Also, after reading it in, you probably want to remove the newline (unless the directory name really does end with a newline):
$p = <STDIN>;
chomp($p);
But if you are just chdiring to be able to run dir and get the results in your script, you probably don't want to do that. First of all, system runs a command but doesn't capture its output. Secondly, you can just do:
opendir my $dirhandle, $p or die "unable to open directory $p: $!\n";
my #files = readdir $dirhandle;
closedir $dirhandle;
and avoid the chdir and running a command prompt command altogether.
I will use it this way.
chdir "C:/Users/Server/Desktop"
The above works for me
Guys im really confused now. Im new to learning Perl. The book ive read sometimes do Perl codes and sometimes do Linux commands.
Is there any connection between them? (Perl codes and linux commands)
I want to open multiple files using Perl code, i know how to open a single file in Perl using:
open (MYFILE,'somefileshere');
and i know how to view multiple files in Linux using ls command.
So how to do this? can i use ls in perl? And i want to open certain files only (perl files) which dont have file extension visible (I cant use *.txt or etc. i guess)
A little help guys
Use system function to execute linux command, glob - for get list of files.
http://perldoc.perl.org/functions/system.html
http://perldoc.perl.org/functions/glob.html
Like:
my #files = glob("*.h *.m"); # matches all files with a .h or .m extension
system("touch a.txt"); # linux command "touch a.txt"
Directory handles are also quite nice, particularly for iterating over all the files in a directory. Example:
opendir(my $directory_handle, "/path/to/directory/") or die "Unable to open directory: $!";
while (my $file_name = <$directory_handle>) {
next if $file_name =~ /some_pattern/; # Skip files matching pattern
open (my $file_handle, '>', $file_name) or warn "Could not open file '$file_name': $!";
# Write something to $file_name. See <code>perldoc -f open</code>.
close $file_handle;
}
closedir $directory_handle;
I am fetching some log files (which are in txt format) from another server and trying to parse them using my Perl script. The logs are being fetched correctly after which I set permissions to 777 for the log directory.
After this I attempt to open the log files, one by one for parsing, via my Perl script. Now, the strange thing and the problem which happens is, my script is sometimes able to open the file and sometimes NOT. To put it simply, it's unable to open the log files for parsing at times.
Also, I have cronned this perl script and the chances of file open failing are greater when it runs via cron rather than manually, although they have run successfully in both cases previously. I don't understand where the issue lies.
Here is the code which I use for opening the files,
$inputDir = "/path/to/dir";
#inputFiles = <$inputDir/*>;
# inputFiles array is list of files in the log directory
foreach my $logFile(#inputFiles)
{
# just to ensure file name is text
$logFile = $logFile."";
# process file only if filename contains "NOK"
if(index($logFile,"NOK") > -1)
{
# opens the file
open($ifile, '<', $logFile) or die "Error: Unable to open file for processing.";
# file parsing takes place
}
}
close($ifile);
I want to re-iterate that this code HAS run successfully and I haven't changed any part of it. Yet, it does not run every time without fail, because its unable to open the log file at times. Any ideas?
You should include the error message $! and the file name $logFile in your die string to see why the open failed, and for which file.
open($ifile, '<', $logFile) or die "Error: Unable to open $logFile: $!";
Also, this line:
$logFile = $logFile."";
...is quite redundant. If a conversion is necessary, perl will handle it.
Just as an example, this is what you code should look like. You may like to try this version
use strict;
use warnings;
my $inputDir = '/path/to/dir';
my #inputFiles = <$inputDir/*>;
foreach my $logFile (grep /NOK/, #inputFiles) {
open my $ifile, '<', $logFile or die qq(Unable to open "$logFile": $!);
# Process data from <$ifile>;
}
Maybe opening some files fails, because your program has too many open files. Your program opens all files in $inputDir and processes them in the loop. After that it closes the last file opened.
EDIT: after reading TLP's comment and reading perldoc -f close and perldoc -f open I see that TLP is right and the filehandle in $ifile is closed by a subsequent open($ifile,'<',$logFile) . However, if the file parsing code not shown by the topic creator creates another reference to $ifile the file handle would stay open.
Moving the call to close into the if block should solve your problem:
$inputDir = "/path/to/dir";
#inputFiles = <$inputDir/*>;
# inputFiles array is list of files in the log directory
foreach my $logFile(#inputFiles)
{
# process file only if filename contains "NOK"
if(index($logFile,"NOK") > -1)
{
# opens the file
# added my to $ifile to keep local to this scope
open(my $ifile, '<', $logFile) or die "Error: Unable to open file for processing.";
# file parsing takes place
# close current file
close($ifile);
}
}