I'm new to Perl and trying to put output files in a different directory.piece of code is as below
use File::Basename;
use File::Copy;
use File::Path;
foreach my $file (sort({uc($a) cmp uc($b)} keys(%$ch_ref))) {
my $num = keys(%{$$ch_ref{$file}});
print "\n -> $string $file ($num):\n";
foreach my $sid (keys(%{$$ch_ref{$file}})) {
if ($type == $PRINT_OLD) {
open ( my $output, '>>',$file );
print {$output} " something";
close ( $output ) or die $!;
}
The third argument to open() is the full path to the file that you want to open. Currently, you're just giving it the filename. but you can expand that to include the directory as well.
Something like this:
my $dir = '/path/to/some/directory';
open my $output, '>>', $dir . $string . '_' . $file;
You should really be checking the success of the open() call, and it's a bit easier to give a sensible error message if you build the filename into a variable first.
my $dir = '/path/to/some/directory';
my $filename = "$dir${string}_$file";
open my $output, '>>', $filename
or die "Can't open $filename: $!";
Note that using ${string} instead of $string means that you can use it directly in the string without the name getting tangled up with the following _ character.
I'd also strongly recommend dropping your use of prototypes on your subroutine. Perl prototypes are often far more trouble than they are worth.
Also, there's no need to open() and close() your file so many times. Just open it at the top of the loop (it will be automatically closed at the end as $output goes out of scope).
Related
I'm using with Perl to open two text files, process them and then write the output to another file.
I have a file INPUT were every line is a customer. I will process each line into variables that will be used to substitute text in another file, TEMP. The result should be written into individual files for each customer, OUTPUT.
My program seems to be working on only the first file. The rest of the files remain empty with no output.
#!/usr/bin/perl -w
if ( $#ARGV < 0) {
print "Usage: proj5.pl <mm/dd/yyyy>\n";
exit;
}
my $date = $ARGV[0];
open(INFO, "p5Customer.txt") or die("Could not open p5Customer.txt file\n");
open(TEMP, "template.txt") or die("Could not open template.txt file\n");
my $directory = "Emails";
mkdir $directory unless(-e $directory);
foreach $info (<INFO>){
($email, $fullname, $title, $payed, $owed) = split /,/, $info;
next if($owed < $payed);
chomp($owed);
$filepath = "$directory/$email";
unless(open OUTPUT, '>>'.$filepath){
die "Unable to create '$filepath'\n";
}
foreach $detail (<TEMP>){
$detail =~ s/EMAIL/$email/g;
$detail =~ s/(NAME|FULLNAME)/$fullname/g;
$detail =~ s/TITLE/$title/g;
$detail =~ s/AMOUNT/$owed/g;
$detail =~ s{DATE}{$date}g;
print OUTPUT $detail;
}
close(OUTPUT);
}
close(INFO);
close(TEMP);
As has been said, you need to open your template file again each time you read from it. There's a bunch of other issues with your code too
Always use strict and use warnings 'all' and declare every variable with my as close as possible to where it is first used
$#ARGV is the index of the last element of #ARGV, so $#ARGV < 0 is much better written as #ARGV < 1
You should use lexical file handles, and the three-parameter form of open, so open(INFO, "p5Customer.txt") should be open my $info_fh, '<', "p5Customer.txt"
You should use while instead of for to read from a file
It is easier to use the default variable $_ for short loops
It is pointless to capture a substring in a regular expression if you're not going to use it, so (NAME|FULLNAME) should be NAME|FULLNAME
There is no point in closing input files before the end of your program
It is also much better to use an existing template system, such as
Template::Toolkit
This should work for you
#!/usr/bin/perl
use strict;
use warnings 'all';
if ( #ARGV < 1 ) {
print "Usage: proj5.pl <mm/dd/yyyy>\n";
exit;
}
my $date = $ARGV[0];
open my $info_fh, '<', 'p5Customer.txt' or die qq{Could not open "p5Customer.txt" file: $!};
my $directory = "Emails";
mkdir $directory unless -e $directory;
while ( <$info_fh> ) {
chomp;
my ($email, $fullname, $title, $payed, $owed) = split /,/;
next if $owed < $payed;
open my $template_fh, '<', 'template.txt' or die qq{Could not open "template.txt" file: $!};
my $filepath = "$directory/$email";
open my $out_fh, '>', $filepath or die qq{Unable to create "$filepath": $!};
while ( <$template_fh> ) {
s/EMAIL/$email/g;
s/FULLNAME|NAME/$fullname/g;
s/TITLE/$title/g;
s/AMOUNT/$owed/g;
s/DATE/$date/g;
print $out_fh $_;
}
close($out_fh);
}
Your problem is that the TEMP loop is inside the INPUT loop and so the TEMP loop will end while the INPUT loop is still on the first line of the INPUT file.
Best to store TEMP file data into a hash table and work on the TEMP hash table inside the INPUT loop.
Good luck.
My program is trying to search a string from multiple files in a directory. The code searches for single patterns like perl but fails to search a long string like Status Code 1.
Can you please let me know how to search for strings with multiple words?
#!/usr/bin/perl
my #list = `find /home/ad -type f -mtime -1`;
# printf("Lsit is $list[1]\n");
foreach (#list) {
# print("Now is : $_");
open(FILE, $_);
$_ = <FILE>;
close(FILE);
unless ($_ =~ /perl/) { # works, but fails to find string "Status Code 1"
print "found\n";
my $filename = 'report.txt';
open(my $fh, '>>', $filename) or die "Could not open file '$filename' $!";
say $fh "My first report generated by perl";
close $fh;
} # end unless
} # end For
There are a number of problems with your code
You must always use strict and use warnings at the top of every Perl program. There is little point in delcaring anything with my without strict in place
The lines returned by the find command will have a newline at the end which must be removed before Perl can find the files
You should use lexical file handles (my $fh instead of FILE) and the three-parameter form of open as you do with your output file
$_ = <FILE> reads only the first line of the file into $_
unless ($_ =~ /perl/) is inverted logic, and there's no need to specify $_ as it is the default. You should write if ( /perl/ )
You can't use say unless you have use feature 'say' at the top of your program (or use 5.010, which adds all features available in Perl v5.10)
It is also best to avoid using shell commands as Perl is more than able to do anything that you can using command line utilities. In this case -f $file is a test that returns true if the file is a plain file, and -M $file returns the (floating point) number of days since the file's modification time
This is how I would write your program
#!/usr/bin/perl
use strict;
use warnings;
use 5.010;
for my $file ( glob '/home/ad/*' ) {
next unless -f $file and int(-M $file) == 1;
open my $fh, '<', $file or die $!;
while ( <$fh> ) {
if ( /perl/ ) {
print "found\n";
my $filename = 'report.txt';
open my $out_fh, '>>', $filename or die "Could not open file '$filename': $!";
say $fh "My first report generated by perl";
close $out_fh;
last;
}
}
}
it should have matched unless $_ contains text in different case.
try this.
unless($_ =~ /Status\s+Code\s+1/i) {
Change
unless ($_ =~ /perl/) {
to:
unless ($_ =~ /(Status Code 1)/) {
I am certain the above works, except it's case sensitive.
Since you question it, I rewrote your script to make more sense of what you're trying to accomplish and implement the above suggestion. Correct me if I am wrong, but you're trying to make a script which matches "Status Code 1" in a bunch of files where last modified within 1 day and print the filename to a text file.
Anyways, below is what I recommend:
#!/usr/bin/perl
use strict;
use warnings;
my $output_file = 'report.txt';
my #list = `find /home/ad -type f -mtime -1`;
foreach my $filename (#list) {
print "PROCESSING: $filename";
open (INCOMING, "<$filename") || die "FATAL: Could not open '$filename' $!";
foreach my $line (<INCOMING>) {
if ($line =~ /(Status Code 1)/) {
open( FILE, ">>$output_file") or die "FATAL: Could not open '$output_file' $!";
print FILE sprintf ("%s\n", $filename);
close(FILE) || die "FATAL: Could not CLOSE '$output_file' $!";
# Bail when we get the first match
last;
}
}
close(INCOMING) || die "FATAL: Could not close '$filename' $!";
}
I'm trying to select only the .log files in my directory and then search in those files for the word "unbound" and print the entire line into a new output file with the same name as the log file (number###.log) but with a .txt extension. This is what I have so far:
#!/usr/bin/perl
use strict;
use warnings;
my $path = $ARGV[0];
my $outpath = $ARGV[1];
my #files;
my $files;
opendir(DIR,$path) or die "$!";
#files = grep { /\.log$/} readdir(DIR);
my #out;
my $out;
opendir(OUT,$outpath) or die "$!";
my $line;
foreach $files (#files) {
open (FILE, "$files");
my #line = <FILE>;
my $regex = Unbound;
open (OUT, ">>$out");
print grep {$line =~ /$regex/ } <>;
}
close OUT;
close FILE;
closedir(DIR);
closedir (OUT);
I'm a beginner, and I don't really know how to create a new text file with the acquired output.
Few things I'd suggest to improve this code:
declare your loop iterators within the loop. foreach my $file ( #files ) {
use 3 arg open: open ( my $input_fh, "<", $filename );
use glob rather than opendir then grep. foreach my $file ( <$path/*.txt> ) {
grep is good for extracting things into arrays. Your grep reads the whole file to print it, which isn't necessary. Doesn't matter much if the file is short though.
perltidy is great for reformatting code.
you're opening 'OUT' to a directory path (I think?) which isn't going to work.
$outpath isn't, it's a file. You need to do something different to output to different files. opendir isn't really valid to an output.
because you're using opendir that's actually giving you filenames - not full paths. So you might be in the wrong place to actually open the files. Prepending the path name, doing a chdir are possible solutions. But that's one of the reasons I like glob because it returns a path as well.
So with that in mind - how about:
#!/usr/bin/perl
use strict;
use warnings;
use File::Basename;
#Extract paths
my $input_path = $ARGV[0];
my $output_path = $ARGV[1];
#Error if paths are invalid.
unless (defined $input_path
and -d $input_path
and defined $output_path
and -d $output_path )
{
die "Usage: $0 <input_path> <output_path>\n";
}
foreach my $filename (<$input_path/*.log>) {
# extract the 'name' bit of the filename.
# be slightly careful with this - it's based
# on an assumption which isn't always true.
# File::Spec is a more powerful way of accomplishing this.
# but should grab 'number####' from /path/to/file/number####.log
my $output_file = basename ( $filename, '.log' );
#open input and output filehandles.
open( my $input_fh, "<", $filename ) or die $!;
open( my $output_fh, ">", "$output_path/$output_file.txt" ) or die $!;
print "Processing $filename -> $output_path/$output_file.txt\n";
#iterate input, extracting into $line
while ( my $line = <$input_fh> ) {
#check if $line matches your RE.
if ( $line =~ m/Unbound/ ) {
#write it to output.
print {$output_fh} $line;
}
}
#tidy up our filehandles. Although technically, they'll
#close automatically because they leave scope
close($output_fh);
close($input_fh);
}
Here is a script that takes advantage of Path::Tiny. Now, at this stage of your learning process, you are probably better off understanding #Sobrique's solution, but using modules such as Path::Tiny or Path::Class will make it easier to write these one off scripts more quickly, and correctly.
Also, I didn't really test this script, so watch out for bugs.
#!/usr/bin/env perl
use strict;
use warnings;
use Path::Tiny;
run(\#ARGV);
sub run {
my $argv = shift;
unless (#$argv == 2) {
die "Need source and destination paths\n";
}
my $it = path($argv->[0])->realpath->iterator({
recurse => 0,
follow_symlinks => 0,
});
my $outdir = path($argv->[1])->realpath;
while (my $path = $it->()) {
next unless -f $path;
next unless $path =~ /[.]log\z/;
my $logfh = $path->openr;
my $outfile = $outdir->child($path->basename('.log') . '.txt');
my $outfh;
while (my $line = <$logfh>) {
next unless $line =~ /Unbound/;
unless ($outfh) {
$outfh = $outfile->openw;
}
print $outfh $line;
}
close $outfh
or die "Cannot close output '$outfile': $!";
}
}
Notes
realpath will croak if the path provided does not exist.
Similarly for openr and openw.
I am reading input files line-by-line to keep the memory footprint of the program independent of the sizes of input files.
I do not open the output file until I know I have a match to print to.
When matching a file extension using a regular expression pattern, keep in mind that \n is a valid character in Unix file names, and the $ anchor will match it.
My code displays all files within the directory, But I need it not to display hidden files such as "." and "..".
opendir(D, "/var/spool/postfix/hold/") || die "Can't open directory: $!\n";
while (my $f = readdir(D))
{
print "MailID :$f\n";
}
closedir(D);
It sounds as though you might be wanting to use the glob function rather than readdir:
while (my $f = </var/spool/postfix/hold/*>) {
print "MailID: $f\n";
}
<...> is an alternate way of globbing, you can also just use the function directly:
while (my $f = glob "/var/spool/postfix/hold/*") {
This will automatically skip the hidden files.
Just skip the files you don't want to see:
while (my $f = readdir(D))
{
next if $f eq '.' or $f eq '..';
print "MailID :$f\n";
}
On a Linux system, "hidden" files and folders are those starting with a dot.
It is best to use lexical directory handles (and file handles).
It is also important to always use strict and use warnings at the start of every Perl program you write.
This short program uses a regular expression to check whether each name starts with a dot.
use strict;
use warnings;
opendir my $dh, '/var/spool/postfix/hold' or die "Can't open directory: $!\n";
while ( my $node = readdir($dh) ) {
next if $node =~ /^\./;
print "MailID: $node\n";
}
I'm learning Perl and wrote a small script to open perl files and remove the comments
# Will remove this comment
my $name = ""; # Will not remove this comment
#!/usr/bin/perl -w <- wont remove this special comment
The name of files to be edited are passed as arguments via terminal
die "You need to a give atleast one file-name as an arguement\n" unless (#ARGV);
foreach (#ARGV) {
$^I = "";
(-w && open FILE, $_) || die "Oops: $!";
/^\s*#[^!]/ || print while(<>);
close FILE;
print "Done! Please see file: $_\n";
}
Now when I ran it via Terminal:
perl removeComments file1.pl file2.pl file3.pl
I got the output:
Done! Please see file:
This script is working EXACTLY as I'm expecting but
Issue 1 : Why $_ didn't print the name of the file?
Issue 2 : Since the loop runs for 3 times, why Done! Please see file: was printed only once?
How you would write this script in as few lines as possible?
Please comment on my code as well, if you have time.
Thank you.
The while stores the lines read by the diamond operator <> into $_, so you're writing over the variable that stores the file name.
On the other hand, you open the file with open but don't actually use the handle to read; it uses the empty diamond operator instead. The empty diamond operator makes an implicit loop over files in #ARGV, removing file names as it goes, so the foreach runs only once.
To fix the second issue you could use while(<FILE>), or rewrite the loop to take advantage of the implicit loop in <> and write the entire program as:
$^I = "";
/^\s*#[^!]/ || print while(<>);
Here's a more readable approach.
#!/usr/bin/perl
# always!!
use warnings;
use strict;
use autodie;
use File::Copy;
# die with some usage message
die "usage: $0 [ files ]\n" if #ARGV < 1;
for my $filename (#ARGV) {
# create tmp file name that we are going to write to
my $new_filename = "$filename\.new";
# open $filename for reading and $new_filename for writing
open my $fh, "<", $filename;
open my $new_fh, ">", $new_filename;
# Iterate over each line in the original file: $filename,
# if our regex matches, we bail out. Otherwise we print the line to
# our temporary file.
while(my $line = <$fh>) {
next if $line =~ /^\s*#[^!]/;
print $new_fh $line;
}
close $fh;
close $new_fh;
# use File::Copy's move function to rename our files.
move($filename, "$filename\.bak");
move($new_filename, $filename);
print "Done! Please see file: $filename\n";
}
Sample output:
$ ./test.pl a.pl b.pl
Done! Please see file: a.pl
Done! Please see file: b.pl
$ cat a.pl
#!/usr/bin/perl
print "I don't do much\n"; # comments dont' belong here anyways
exit;
print "errrrrr";
$ cat a.pl.bak
#!/usr/bin/perl
# this doesn't do much
print "I don't do much\n"; # comments dont' belong here anyways
exit;
print "errrrrr";
Its not safe to use multiple loops and try to get the right $_. The while Loop is killing your $_. Try to give your files specific names inside that loop. You can do this with so:
foreach my $filename(#ARGV) {
$^I = "";
(-w && open my $FILE,'<', $filename) || die "Oops: $!";
/^\s*#[^!]/ || print while(<$FILE>);
close FILE;
print "Done! Please see file: $filename\n";
}
or that way:
foreach (#ARGV) {
my $filename = $_;
$^I = "";
(-w && open my $FILE,'<', $filename) || die "Oops: $!";
/^\s*#[^!]/ || print while(<$FILE>);
close FILE;
print "Done! Please see file: $filename\n";
}
Please never use barewords for filehandles and do use a 3-argument open.
open my $FILE, '<', $filename — good
open FILE $filename — bad
Simpler solution: Don't use $_.
When Perl was first written, it was conceived as a replacement for Awk and shell, and Perl heavily borrowed from that syntax. Perl also for readability created the special variable $_ which allowed you to use various commands without having to create variables:
while ( <INPUT> ) {
next if /foo/;
print OUTPUT;
}
The problem is that if everything is using $_, then everything will effact $_ in many unpleasant side effects.
Now, Perl is a much more sophisticated language, and has things like locally scoped variables (hint: You don't use local to create these variables -- that merely gives _package variables (aka global variables) a local value.)
Since you're learning Perl, you might as well learn Perl correctly. The problem is that there are too many books that are still based on Perl 3.x. Find a book or web page that incorporates modern practice.
In your program, $_ switches from the file name to the line in the file and back to the next file. It's what's confusing you. If you used named variables, you could distinguished between files and lines.
I've rewritten your program using more modern syntax, but your same logic:
use strict;
use warnings;
use autodie;
use feature qw(say);
if ( not $ARGV[0] ) {
die "You need to give at least one file name as an argument\n";
}
for my $file ( #ARGV ) {
# Remove suffix and copy file over
if ( $file =~ /\..+?$/ ) {
die qq(File "$file" doesn't have a suffix);
}
my ( $output_file = $file ) =~ s/\..+?$/./; #Remove suffix for output
open my $input_fh, "<", $file;
open my $output_fh, ">", $output_file;
while ( my $line = <$input_fh> ) {
print {$output_fh} $line unless /^\s*#[^!]/;
}
close $input_fh;
close $output_fh;
}
This is a bit more typing than your version of the program, but it's easier to see what's going on and maintain.