I am new to perl. I'm writing below script to print the system boot time information from the windows command "systeminfo". There look some problem here. I'm getting the output like this. Could someone help me.
use strict;
use warnings;
my $filename = 'sysinfo.txt';
my #cmdout = `systeminfo`;
open(my $cmd, '>', $filename) or die "Could not open file '$filename' $!";
print $cmd #cmdout;
foreach my $file (#cmdout) {
open my $cmd, '<:encoding(UTF-8)', $file or die;
while (my $line = <$cmd>) {
if ($line =~ m/.*System Boot.*/i) {
print $line;
}
}
}
Output: Died at perl_sysboottime.pl line 8.
As indicated by the error printed, your script is dying the first time it executes
open my $cmd, '<:encoding(UTF-8)', $file or die;
This means that open failed to open a file.
I'm not familiar with Windows's commands, but I'll go by the example systeminfo output given here.
After executing line 4, the array #cmdout contains the lines output by systeminfo. When line 8 is executed, $file has been set to the first line of the output, or Host Name: COMPUTERHOPE\n in my example (note the trailing newline). This is not a filename, so open fails.
It looks like you're trying to combine two different ways of iterating through the lines of a file, one inside of another. Try something like this:
foreach my $line (#cmdout) {
if ($line =~ m/.*System Boot.*/i) {
print $line;
}
}
Related
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've got a script that reformats an input file and creates an output file. When I try to read that output file for the second part of the script, it doesn't work. However if I split the script into two parts it works fine and gives me the output that I need. I'm not a programmer and surprised I've got this far - I've been banging my head for days trying to resolve this.
My command for running it is this (BTW the temp.txt was just a brute force workaround for getting rid of the final comma to get my final output file - couldn't find another solution):
c:\perl\bin\perl merge.pl F146.sel temp.txt F146H.txt
Input looks like this (from another software package) ("F146.sel"):
/ Selected holes from the .\Mag_F146_Trimmed.gdb database.
"L12260"
"L12270"
"L12280"
"L12290"
Output looks like this (mods to the text: quotes removed, insert comma, concatenate into one line, remove the last comma) "F146H.txt":
L12260,L12270,L12280,L12290
Then I want to use this as input in the next part of the script, which basically inserts this output into a line of code that I can use in another software package (my "merge.gs" file). This is the output that I get if I split my script into two parts, but it just gives me a blank if I do it as one (see below).
CURRENT Database,"RAD_F146.gdb"
SETINI MERGLINE.OUT="DALL"
SETINI MERGLINE.LINES="L12260,L12270,L12280,L12290"
GX mergline.gx
What follows is my "merge.pl". What have I done wrong?
(actually, the question could be - what haven't I done wrong, as this is probably the most retarded code you've seen in a while. In fact, I bet some of you could get this entire operation done in 10-15 lines of code, instead of my butchered 90. Thanks in advance.)
# this reformats the SEL file to remove the first line and replace the " with nothing
$file = shift ;
$temp = shift ;
$linesH = shift ;
#open (Profiles, ">.\\scripts\\P2.gs")||die "couldn't open output .gs file";
open my $in, '<', $file or die "Can't read old file: Inappropriate I/O control operation";
open my $out, '>', $temp or die "Can't write new file: Inappropriate I/O control operation";
my $firstLine = 1;
while( <$in> )
{
if($firstLine)
{
$firstLine = 0;
}
else{
s/"L/L/g; # replace "L with L
s/"/,/g; # replace " with,
s|\s+||; # concatenates it all into one line
print $out $_;
}
}
close $out;
open (part1, "${temp}")||die "Couldn't open selection file";
open (part2, ">${linesH}")||die "Couldn't open selection file";
printitChomp();
sub printitChomp
{
print part2 <<ENDGS;
ENDGS
}
while ($temp = <part1> )
{
print $temp;
printit();
}
sub printit
{$string = substr (${temp}, 0,-1);
print part2 <<ENDGS;
$string
ENDGS
}
####Theoretically this creates the merge script from the output
####file from the previous loop. However it only seems to work
####if I split this into 2 perl scripts.
open (MergeScript, ">MergeScript.gs")||die "couldn't open output .gs file";
printitMerge();
open (SEL, "${linesH}")||die "Couldn't open selection file";
sub printitMerge
#open .sel file
{
print MergeScript <<ENDGS;
ENDGS
}
#iterate over required files
while ( $line = <SEL> ){
chomp $line;
print STDOUT $line;
printitLines();
}
sub printitLines
{
print MergeScript <<ENDGS;
CURRENT Database,"RAD_F146.gdb"
SETINI MERGLINE.OUT="DALL"
SETINI MERGLINE.LINES="${line}"
GX mergline.gx
ENDGS
}
so I think all you were really missing was close(part2); to allow it to be reopened as SEL..
#!/usr/bin/env perl
use strict;
use warnings;
# this reformats the SEL file to remove the first line and replace the " with nothing
my $file = shift;
my $temp = shift;
my $linesH = shift;
open my $in, '<', $file or die "Can't read old file: Inappropriate I/O control operation";
open my $out, '>', $temp or die "Can't write new file: Inappropriate I/O control operation";
my $firstLine = 1;
while (my $line = <$in>){
print "LINE: $line\n";
if ($firstLine){
$firstLine = 0;
} else {
$line =~ s/"L/L/g; # replace "L with L
$line =~ s/"/,/g; # replace " with,
$line =~ s/\s+//g; # concatenates it all into one line
print $out $line;
}
}
close $out;
open (part1, $temp) || die "Couldn't open selection file";
open (part2, ">", $linesH) || die "Couldn't open selection file";
while (my $temp_line = <part1>){
print "TEMPLINE: $temp_line\n";
my $string = substr($temp_line, 0, -1);
print part2 <<ENDGS;
$string
ENDGS
}
close(part2);
#### this creates the merge script from the output
#### file from the previous loop.
open (MergeScript, ">MergeScript.gs")||die "couldn't open output .gs file";
open (SEL, $linesH) || die "Couldn't open selection file";
#iterate over required files
while ( my $sel_line = <SEL> ){
chomp $sel_line;
print STDOUT $sel_line;
print MergeScript <<"ENDGS";
CURRENT Database,"RAD_F146.gdb"
SETINI MERGLINE.OUT="DALL"
SETINI MERGLINE.LINES="$sel_line"
GX mergline.gx
ENDGS
}
and one alternative way of doing it..
#!/usr/bin/env perl
use strict;
use warnings;
my $file = shift;
open my $in, '<', $file or die "Can't read old file: Inappropriate I/O control operation";
my #lines = <$in>; # read in all the lines
shift #lines; # discard the first line
my $line = join(',', #lines); # join the lines with commas
$line =~ s/[\r\n"]+//g; # remove the quotes and newlines
# print the line into the mergescript
open (MergeScript, ">MergeScript.gs")||die "couldn't open output .gs file";
print MergeScript <<"ENDGS";
CURRENT Database,"RAD_F146.gdb"
SETINI MERGLINE.OUT="DALL"
SETINI MERGLINE.LINES="$line"
GX mergline.gx
ENDGS
I have created a file using:
open OUT, ">$outfile";
print OUT "$file_in;$system_in;$symbol_in;$price_in\n";
and trying later to read from this file:
open DATAIN, "<", "$outfile" or die $!;
while(<DATAIN>)
{
chomp($_);
my #ld = split(/\;/,$_);
my $system = $ld[1];
my $file = $ld[0];
...
print "HELLOOO?$file\t$system\..";
}
but in the first iteration, it gives me this error:
Can't use an undefined value as an ARRAY reference
The problem is really in the \n
with which I created the new lines in the file that I am trying to read afterwards.
I tried with \r too, the error is not there, but then it reads all as one line.
Any help please? Thanks a lot in advance!
Full code:
open OUT, ">$outfile";
print OUT "$file_in;$system_in;$symbol_in;$price_in\n";
open my $fh, "<", "$outfile" or die $!;
while(<$fh>)
{
chomp;
my #ld = split(/\;/);
my $system = $ld[1];
my $file = $ld[0];
my $symbol = $ld[2];
my $price = $ld[3];
my $key = $file . $symbol;
print "HELLOOO?$file\t$system\t$symbol\t$price\n"
}
Error:
Can't use an undefined value as an ARRAY reference at C:/Perl/lib/Math/BigInt/Calc.pm line 476, <fh> line1.
The error is when it reads the line from the file. If in the initial file I put /r instead of /n, I don't get this error, but all the file is read as one line.
You're invoking the <> operator incorrectly.
You should not be using the filehandle DATA.
You should use lexical filehandles.
You do not need to pass $_ to chomp or split. That's why $_ exists.
Here's how you want to do it.
open my $fh, '<', $outfile or die $!;
while(<$fh>) {
chomp;
my #ld = split(/\;/);
...
}
I want to extract rows from a file that match a particular pattern and I want to do this for over 500 files. It should have the ability to retain the unique name of the file as well.
I used awk but then i have to do each file individually.
c:\>gawk "/S1901/" Census_Tract_*.csv > Census_Tract_*.csv
In the example shown in the link here (http://bit.ly/nMX8qh) I want to retain only those records that have S1901 in them. Apologies for the external link but i am not able to retain formatting of the table.
I found some perl code that I used to write it but it retains all the rows and does not select only those rows/records where the pattern matches. Any tips would be much appreciated. The perl code is below:
#perl -w
$pattern = "Subject_Census*.csv"; # process only those files that match pattern
while (defined ($in = glob($pattern))) {
($out = $in) =~ s/\.csv$/.outcsv/; # read from "xyz.in" and write to "xyz.out"
open (IN, "<", $in) or die "Can't open $in for reading: $!";
open (OUT,">>", $out) or die "Can't open $out for writing: $!";
while (<IN>) {
$mystring =~ /S1901/;
print OUT $_ if $mystring == 0;
}
close (IN) or die "Can't close $in: $!"; # good idea to do some housekeeping
close (OUT) or die "Can't close $out: $!";
}
Untested:
use strict;
use warnings;
use autodie;
my $files_list_filename = 'files.txt';
open my $fl, '<', $files_list_filename;
my #list_of_files = <$fl>;
chomp #list_of_files;
close $fl;
foreach my $file ( #list_of_files ) {
open my $test_fh, '<', $file;
while ( my $line = <$test_fh> ) {
if( $line =~ m/S1901/ ) {
print "$file at $.: $line";
}
}
close $test_fh;
}
Is that sort of what you had in mind? It opens a file named filelist.txt and reads in a list of however many filenames you want to give it. Then it iterates over that list, opening each file one by one, scanning each file one by one, and if a line is found containing the trigger text, it prints the filename and line number, as well as the line itself where the trigger was met. Then it moves on to the next.
perl -ni.bak -e 'print if /S1901/' Subject_Census*.csv
I want to remove all lines in a text file that start with HPL_ I have acheived this and can print to screen, but when I try to write to a file, I just get the last line of the amended text printed in the new file. Any help please!
open(FILE,"<myfile.txt");
#LINES = <FILE>;
close(FILE);
open(FILE,">myfile.txt");
foreach $LINE (#LINES) {
#array = split(/\:/,$LINE);
my $file = "changed";
open OUTFILE, ">$file" or die "unable to open $file $!";
print OUTFILE $LINE unless ($array[0] eq "HPL_");
}
close(FILE);
close (OUTFILE);
exit;
You just want to remove all lines that start with HPL_? That's easy!
perl -pi -e 's/^HPL_.*//s' myfile.txt
Yes, it really is just a one-liner. :-)
If you don't want to use the one-liner, re-write the "write to file" portion as follows:
my $file = "changed";
open( my $outfh, '>', $file ) or die "Could not open file $file: $!\n";
foreach my $LINE (#LINES) {
my #array = split(/:/,$LINE);
next if $array[0] eq 'HPL_';
print $outfh $LINE;
}
close( $outfh );
Note how you are open()ing the file each time through the loop. This is causing the file to only contain the last line, as using open() with > means "overwrite what's in the file". That's the major problem with your code as it stands.
Edit: As an aside, you want to clean up your code. Use lexical filehandles as I've shown. Always add the three lines that tchrist posted at the top of every one of your Perl programs. Use the three-operator version of open(). Don't slurp the entire file into an array, as if you try to read a huge file it could cause your computer to run out of memory. Your program could be re-written as:
#!perl
use strict;
use autodie;
use warnings FATAL => "all";
my $infile = "myfile.txt";
my $outfile = "changed.txt";
open( my $infh, '<', $infile );
open( my $outfh, '>', $outfile );
while( my $line = <$infh> ) {
next if $line =~ /^HPL_/;
print $outfh $line;
}
close( $outfh );
close( $infh );
Note how with use autodie you don't need to add or die ... to the open() function, as the autodie pragma handles that for you.
The issue with your code is that you open the file for output within your line-processing loop which, due to your use of the '>' form of open, opens the file each time for write, obliterating any previous content.
Move the invocation of open() to the top of your file, above the loop, and it should work.
Also, I'm not sure of your intent but at line 4 of your example, you reopen your input file for write (using '>'), which also clobbers anything it contains.
As a side note, you might try reading up on Perl's grep() command which is designed to do exactly what you need, as in:
#!/usr/bin/perl
use strict;
use warnings;
open(my $in, '<', 'myfile.txt') or die "failed to open input for read: $!";
my #lines = <$in> or die 'no lines to read from input';
close($in);
# collect all lines that do not begin with HPL_ into #result
my #result = grep ! /^HPL_/, #lines;
open(my $out, '>', 'changed.txt') or die "failed to open output for write: $!";
print { $out } #result;
close($out);