I am new to perl, we have a log file similar to below:
SQL> #D:\Luntbuild_Testing\ASCMPK\Files\MAIN\DATABASE\HOST\FILES\DDL\20120412_152632__1_CLTM_EVENT_ACC_ROLE_BLOCK.DDL
SQL> CREATE TABLE CLTM_EVENT_ACC_ROLE_BLOCK
2 (
3 EVENT_CODE VARCHAR2(4) ,
4 ACC_ROLE VARCHAR2(20)
5 )
6 ;
CREATE TABLE CLTM_EVENT_ACC_ROLE_BLOCK
*
ERROR at line 1:
ORA-00955: name is already used by an existing object
SQL> #D:\Luntbuild_Testing\ASCMPK\Files\MAIN\DATABASE\HOST\FILES\DDL\20120412_173845__2_CLTM_EVENT_ACC_ROLE_BLOCK.DDL
SQL> DROP TABLE CLTM_EVENT_ACC_ROLE_BLOCK;
Table dropped.
Now I need a script to display only the script paths that have ORA-XXX errors, script should display only the path of the SQL> #D:\Luntbuild_Testing\ associated with ORA-xxx errors, I have tried below can you please help me to enhance the same.
$file = 'c:\data.txt';
open(txt, $file);
while($line = <txt>) {
print "$line" if $line =~ /> #/; #here i want the output to display the path of the script with only ORA-xxx errors and ignore if there are no errors
print "$line" if $line =~ /ORA-/;
}
close(txt);
Instead of immediately printing the line when you see the > # marker, store it in a variable, and only print it out if and when you actually see an error:
$file = 'c:\data.txt';
open(txt, $file);
while($line = <txt>) {
$fn = $line if $line =~ /> #/; #here i want the output to display the path of the script with only ORA-xxx errors and ignore if there are no errors
print $fn, $line if $line =~ /ORA-/;
}
close(txt);
Also: it's good practice to write use strict; and use warnings; at the top of your script. use strict; forces you to explicitly name your local variables with my, which catches a lot of errors due to misspellings.
I would do something pretty similar to what you tried:
$file = 'c:\data.txt';
open(F, $file);
my $last_cmd = '';
while (<F>) {
$last_cmd = $_ if /^SQL\> \#D:/;
print $last_cmd if /^ORA-/;
}
Related
I have a simple text file that includes all 50 states. I want the user to enter a word and have the program return the line the specific state is on in the file or otherwise display a "word not found" message. I do not know how to use find. Can someone assist with this? This is what I have so far.
#!/bin/perl -w
open(FILENAME,"<WordList.txt"); #opens WordList.txt
my(#list) = <FILENAME>; #read file into list
my($state); #create private "state" variable
print "Enter a US state to search for: \n"; #Print statement
$line = <STDIN>; #use of STDIN to read input from user
close (FILENAME);
An alternative solution that reads only the parts of the file until a result is found, or the file is exhausted:
use strict;
use warnings;
print "Enter a US state to search for: \n";
my $line = <STDIN>;
chomp($line);
# open file with 3 argument open (safer)
open my $fh, '<', 'WordList.txt'
or die "Unable to open 'WordList.txt' for reading: $!";
# read the file until result is found or the file is exhausted
my $found = 0;
while ( my $row = <$fh> ) {
chomp($row);
next unless $row eq $line;
# $. is a special variable representing the line number
# of the currently(most recently) accessed filehandle
print "Found '$line' on line# $.\n";
$found = 1; # indicate that you found a result
last; # stop searching
}
close($fh);
unless ( $found ) {
print "'$line' was not found\n";
}
General notes:
always use strict; and use warnings; they will save you from a wide range of bugs
3 argument open is generally preferred, as well as the or die ... statement. If you are unable to open the file, reading from the filehandle will fail
$. documentation can be found in perldoc perlvar
Tool for the job is grep.
chomp ( $line ); #remove linefeeds
print "$line is in list\n" if grep { m/^\Q$line\E$/g } #list;
You could also transform your #list into a hash, and test that, using map:
my %cities = map { $_ => 1 } #list;
if ( $cities{$line} ) { print "$line is in list\n";}
Note - the above, because of the presence of ^ and $ is an exact match (and case sensitive). You can easily adjust it to support fuzzier scenarios.
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.
I am trying to parse a CSV file to read in all the other zip codes. I am trying to create a hash where each key is a zip code and the value is the number it appears in the file. Then I want to print out the contents as Zip Code - Number. Here is the Perl script I have so far.
use strict;
use warnings;
my %hash = qw (
zipcode count
);
my $file = $ARGV[0] or die "Need CSV file on command line \n";
open(my $data, '<', $file) or die "Could not open '$file $!\n";
while (my $line = <$data>) {
chomp $line;
my #fields = split "," , $line;
if (exists($hash{$fields[2]})) {
$hash{$fields[1]}++;
}else {
$hash{$fields[1]} = 1;
}
}
my $key;
my $value;
while (($key, $value) = each(%hash)) {
print "$key - $value\n";
}
exit;
You don't say which column your zip code is in, but you are using the third field to check for an existing hash element, and then the second field to increment it.
There is no need to check whether a hash element already exists: Perl will happily create a non-existent hash element and increment it to 1 the first time you access it.
There is also no need to explicitly open any files passed as command line parameters: Perl will open them and read them if you use the <> operator without a file handle.
This reworking of your own program may work. It assumes the zip code is in the second column of the CSV. If it is anywhere else just change ++$hash{$fields[1]} appropriately.
use strict;
use warnings;
#ARGV or die "Need CSV file on command line \n";
my %counts;
while (my $line = <>) {
chomp $line;
my #fields = split /,/, $line;
++$counts{$fields[1]};
}
while (my ($key, $value) = each %counts) {
print "$key - $value\n";
}
Sorry if this is off-topic, but if you're on a system with the standard Unix text processing tools, you could use this command to count the number of occurrences of each value in field #2, and not need to write any code.
cut -d, -f2 filename.csv | sort | uniq -c
which will generate something like this output, where the count is listed first, and the zipcode second:
12 12345
2 56789
34 78912
1 90210
I'm new to Perl and I have a CSV file that contains e-mails and names, like this:
john#domain1.com;John
Paul#domain2.com;
Richard#domain3.com;Richard
Rob#domain4.com;
Andrew#domain5.com;Andrew
However, as you can see a few entries/lines have the e-mail address and the ; field separator, but lack the name. I need to read line by line and and if the name field is missing, I want to print in this place the begin of the e-mail until #domainX.com. Output example:
john#domain1.com;John
Paul#domain2.com;Paul
Richard#domain3.com;Richard
Rob#domain4.com;Rob
Andrew#domain5.com;Andrew
I'm new with Perl, I did the iteration of read line by line, such this:
#!/usr/bin/perl
use warnings;
use strict;
open (MYFILE, 'test.txt');
while (<MYFILE>) {
chomp;
}
But I'm failing to parse the entries to use ; as a separator and to check if the name field is missing and consequently print the begin of the e-mail without the domain.
Can someone please give me a example based on my code?
First, if the file may contain real CSV (or space SV in your case) data (e.g. quoted fields), I'd strongly recommend using a standard Perl module to parse it.
Otherwise, a quick-and-dirty example can be:
#!/usr/bin/perl
use warnings;
use strict;
# In modern Perl, please always use 3-aqr form of open and lexical filehandles.
# More robust
open $fh, "<", 'test.txt' || die "Can not open: $!\n";
while (<$fh>) {
chomp;
my ($email, name) = split(/;/, $_);
if (!$name) {
my ($userid, $domain) = split(/\#/, $email);
$name = $userid;
}
print "$space_prefix$email;$name\n"; # Print to STDOUT for simplicity of example
}
close($fh);
Try:
#!/usr/bin/env perl
use strict;
use warnings;
for my $file ( #ARGV ){
open my$in_fh, '<', $file or die "could not open $file: $!\n";
while( my $line = <$in_fh> ){
chomp( $line );
my ( $email, $name ) = split m{ \; }msx, $line;
if( ! ( defined $name && length( $name ) > 0 ) ){
( $name ) = split m{ \# }msx, $email;
$name = ucfirst( lc( $name ));
}
print "$email;$name\n";
}
}
I am not a pearl programmer, but I would split first on the space character, and then you could iterate through the results and split by the semi-colon. Then you can check the second member of the semi-colon split array, and if it is empty, replace it with the beginning of the first member of the semi-colon split array. Then, just reverse the process, first joining by semi-colons and then by spaces.
I need some perl help in putting these (2) processes/code to work together. I was able to get them working individually to test, but I need help bringing them together especially with using the loop constructs. I'm not sure if I should go with foreach..anyways the code is below.
Also, any best practices would be great too as I'm learning this language. Thanks for your help.
Here's the process flow I am looking for:
read a directory
look for a particular file
use the file name to strip out some key information to create a newly processed file
process the input file
create the newly processed file for each input file read (if i read in 10, I create 10 new files)
Part 1:
my $target_dir = "/backups/test/";
opendir my $dh, $target_dir or die "can't opendir $target_dir: $!";
while (defined(my $file = readdir($dh))) {
next if ($file =~ /^\.+$/);
#Get filename attributes
if ($file =~ /^foo(\d{3})\.name\.(\w{3})-foo_p(\d{1,4})\.\d+.csv$/) {
print "$1\n";
print "$2\n";
print "$3\n";
}
print "$file\n";
}
Part 2:
use strict;
use Digest::MD5 qw(md5_hex);
#Create new file
open (NEWFILE, ">/backups/processed/foo$1.name.$2-foo_p$3.out") || die "cannot create file";
my $data = '';
my $line1 = <>;
chomp $line1;
my #heading = split /,/, $line1;
my ($sep1, $sep2, $eorec) = ( "^A", "^E", "^D");
while (<>)
{
my $digest = md5_hex($data);
chomp;
my (#values) = split /,/;
my $extra = "__mykey__$sep1$digest$sep2" ;
$extra .= "$heading[$_]$sep1$values[$_]$sep2" for (0..scalar(#values));
$data .= "$extra$eorec";
print NEWFILE "$data";
}
#print $data;
close (NEWFILE);
You are using an old-style of Perl programming. I recommend you to use functions and CPAN modules (http://search.cpan.org). Perl pseudocode:
use Modern::Perl;
# use...
sub get_input_files {
# return an array of files (#)
}
sub extract_file_info {
# takes the file name and returs an array of values (filename attrs)
}
sub process_file {
# reads the input file, takes the previous attribs and build the output file
}
my #ifiles = get_input_files;
foreach my $ifile(#ifiles) {
my #attrs = extract_file_info($ifile);
process_file($ifile, #attrs);
}
Hope it helps
I've bashed your two code fragments together (making the second a sub that the first calls for each matching file) and, if I understood your description of the objective correctly, this should do what you want. Comments on style and syntax are inline:
#!/usr/bin/env perl
# - Never forget these!
use strict;
use warnings;
use Digest::MD5 qw(md5_hex);
my $target_dir = "/backups/test/";
opendir my $dh, $target_dir or die "can't opendir $target_dir: $!";
while (defined(my $file = readdir($dh))) {
# Parens on postfix "if" are optional; I prefer to omit them
next if $file =~ /^\.+$/;
if ($file =~ /^foo(\d{3})\.name\.(\w{3})-foo_p(\d{1,4})\.\d+.csv$/) {
process_file($file, $1, $2, $3);
}
print "$file\n";
}
sub process_file {
my ($orig_name, $foo_x, $name_x, $p_x) = #_;
my $new_name = "/backups/processed/foo$foo_x.name.$name_x-foo_p$p_x.out";
# - From your description of the task, it sounds like we actually want to
# read from the found file, not from <>, so opening it here to read
# - Better to use lexical ("my") filehandle and three-arg form of open
# - "or" has lower operator precedence than "||", so less chance of
# things being grouped in the wrong order (though either works here)
# - Including $! in the error will tell why the file open failed
open my $in_fh, '<', $orig_name or die "cannot read $orig_name: $!";
open(my $out_fh, '>', $new_name) or die "cannot create $new_name: $!";
my $data = '';
my $line1 = <$in_fh>;
chomp $line1;
my #heading = split /,/, $line1;
my ($sep1, $sep2, $eorec) = ("^A", "^E", "^D");
while (<$in_fh>) {
chomp;
my $digest = md5_hex($data);
my (#values) = split /,/;
my $extra = "__mykey__$sep1$digest$sep2";
$extra .= "$heading[$_]$sep1$values[$_]$sep2"
for (0 .. scalar(#values));
# - Useless use of double quotes removed on next two lines
$data .= $extra . $eorec;
#print $out_fh $data;
}
# - Moved print to output file to here (where it will print the complete
# output all at once) rather than within the loop (where it will print
# all previous lines each time a new line is read in) to prevent
# duplicate output records. This could also be achieved by printing
# $extra inside the loop. Printing $data at the end will be slightly
# faster, but requires more memory; printing $extra within the loop and
# getting rid of $data entirely would require less memory, so that may
# be the better option if you find yourself needing to read huge input
# files.
print $out_fh $data;
# - $in_fh and $out_fh will be closed automatically when it goes out of
# scope at the end of the block/sub, so there's no real point to
# explicitly closing it unless you're going to check whether the close
# succeeded or failed (which can happen in odd cases usually involving
# full or failing disks when writing; I'm not aware of any way that
# closing a file open for reading can fail, so that's just being left
# implicit)
close $out_fh or die "Failed to close file: $!";
}
Disclaimer: perl -c reports that this code is syntactically valid, but it is otherwise untested.