i am trying to put some word in tempfile via commandline
temp file creat but word not past in tempfile
#!/usr/bin/perl -w
system ('clear');
$TMPFILE = "mktemp /tmp/myfile/devid.XXXXXXXXXX";
$echo = "echo /"hello world/" >$TMPFILE";
system ("$TMPFILE");
system ("$echo");
Please Help to Solve This
To capture the name output by mktemp, do this instead:
chomp($TMPFILE = `mktemp /tmp/myfile/devid.XXXXXXXXXX`);
But Perl can do all the things you are doing without resorting to the shell.
Avoid using external commands from perl script as much as possible.
you can use: File::Temp module in this case, see this
Here's a specific demonstration of the advice that others have given you: where possible, use Perl directly rather than invoking system. Also, you should get in the habit of including use strict and use warnings in your Perl scripts.
use strict;
use warnings;
use File::Temp;
my $ft = File::Temp->new(
UNLINK => 0,
TEMPLATE => '/tmp/myfile/devid.XXXXXXXXXX',
);
print "Writing to temp file: ", $ft->filename, "\n";
print $ft "Hello, world.\n";
Related
I treid one of my previous example to pass input and output files via command line arguments using perl?
Previous example:
[Is it possible to add the file out in the File::Find::Rule using perl?
code which i tried to add input and output file as command line arguments:(generate.pl).I got struck how to include command line arguments to read and copy the files along with perl modules.
use strict;
use warnings 'all';
use CGI qw(:all);
#generate the user file arguments
use Getopt::Long 'GetOptions';
use File::Path qw( make_path );
use File::Copy qw( copy move);
use File::Find::Rule qw( );
GetOptions(
'prjroot=s' => \my $input_dir,
'outdir=s' => \my $output_dir,
);
my %created;
for my $in (
File::Find::Rule
->file()
->name(qr/^[^.].*\.yfg$/)
->in($input_dir)
) {
my $match_file = substr($in, length($input_dir) + 1);
my ($match_dir) = $match_file =~ m{^(.*)/} ? $1 : '.';
my $out_dir = $output_dir . '/' . $match_dir;
my $out = $output_dir . '/' . $match_file;
make_path($out_dir) if !$created{$out_dir}++;
copy($in, $out);
}
Error occured:
./generate.pl: line 1: use: command not found
./generate.pl: line 2: use: command not found
./generate.pl: line 3: syntax error near unexpected token `('
./generate.pl: line 3: `use CGI qw(:all);'
perl execution should be as follows:
I should copy the contents from one directory to another directory along with perl modulES(I.E File::Find::Rule)
./generate.pl -prjroot "/home/bharat/DATA" -outdir "/home/bharat/DATA1"
Help me fix my issues .
You miss the perl comment in the first line:
#!<path_to_perl>/perl
use strict;
use warnings 'all';
use CGI qw(:all);
#generate the user file arguments
.....
Your program will also work if you call it with the perl Interpreter in front of your command:
perl ./generate.pl -prjroot "/home/bharat/DATA" -outdir "/home/bharat/DATA1"
You've already seen what the problem is. But I'll just add that perldoc perldiag gives pretty good explanations for any error message you get from Perl. In this case, searching for "command not found" would give you this:
%s: Command not found
(A) You've accidentally run your script through csh or another shell instead of Perl. Check the #! line, or manually feed your script into Perl yourself. The #! line at the top of your file could look like
#!/usr/bin/perl -w
And that's particularly impressive, given that this error isn't actually generated by Perl - but by your shell.
I am trying to extract a directory with tar files, but it doesn't seem to work correctly .
The command works in command line, but not with the "system" in perl. I really need this to work in perl.
$tar_dir = "/root/updates/*.tar.bz2";
system ("for i in $tar_dir ; do tar xvfj $i; done");
Works on command line like this : for i in *.bz2 ; do tar xvfj $i; done
Am i missing something ?
Thanks
Or, you could move the loop into the Perl code:
use warnings;
use strict;
for (glob '/root/updates/*.tar.bz2') {
system "tar xvfj $_";
}
Yes, you forgot to escape $i in the string in perl.
Try:
system ("for i in $tar_dir ; do tar xvfj \$i; done");
If you don't escape it, then it will get expanded just like $tar_dir. Make sure you have use strict; and use warnings; at the top of your perl script, it will help a bit with this sort of thing (if $i wasn't defined in the perl script in this case, you'd have got a message from perl telling you about the problem.)
I'm not sure if importing is the right word to use. I'm a beginner in both Perl and Bash. I have set a variable on Bash, so when I do:
echo $PRDIR
it prints a string (It's a directory name)
I want to import that string to Perl, and I don't know how to do that. I've tried:
$varex = system("$PRDIR");
print "$varex";
And also
$varex = system("echo $PRDIR");
print "$varex";
but that doesn't work (I understand the last one, It prints "0" because that's echo's return value). I've also tried redirecting stdout to a variable but I couldn't.
If you want Bash to export a variable into the environment so it's accessible to programs, you can use the export builtin:
export PRDIR
Inside Perl, you would then access it using the %ENV hash:
my $varex = $ENV{"PRDIR"};
print "\$varex is: $varex\n";
Another solution to use the variable directly in perl :
In the shell :
$ export PRDIR=foobar
In perl :
#!/usr/bin/perl
use Modern::Perl;
use Env qw/PRDIR/;
say $PRDIR;
I guess you need something like this:
use Cwd 'abs_path';
use File::Basename;
my $self = abs_path($0);
my $bindir = dirname( abs_path($0) );
unless ($ENV{APP_ENV}) {
warn "No APP_ENV, will try to get from bin/env.sh";
exec("source $bindir/env.sh && /usr/bin/perl $self") || die "$!";
}
I have env.sh in my bin folder with following content:
export APP_ENV=development
The idea behind this approach is that I don't need to bother if I set my ENV variables before running my Perl code or forget to do it. I need just to run my Perl program and it will take care about preparing environment for itself.
Trying to run this little perl program from parsCit:
parsCit-client.pl e1.txt
Too late for -CSD option at [filename] line 1
e1.txt is here: http://dl.dropbox.com/u/10557283/parserProj/e1.txt
I'm running the program from win7 cmd, not Cygwin.
filename is parsCit-client.pl - entire program is here:
#!/usr/bin/perl -CSD
#
# Simple SOAP client for the ParsCit web service.
#
# Isaac Councill, 07/24/07
#
use strict;
use encoding 'utf8';
use utf8;
use SOAP::Lite +trace=>'debug';
use MIME::Base64;
use FindBin;
my $textFile = $ARGV[0];
my $repositoryID = $ARGV[1];
if (!defined $textFile || !defined $repositoryID) {
print "Usage: $0 textFile repositoryID\n".
"Specify \"LOCAL\" as repository if using local file system.\n";
exit;
}
my $wsdl = "$FindBin::Bin/../wsdl/ParsCit.wsdl";
my $parsCitService = SOAP::Lite
->service("file:$wsdl")
->on_fault(
sub {
my($soap, $res) = #_;
die ref $res ? $res->faultstring :
$soap->transport->status;
});
my ($citations, $citeFile, $bodyFile) =
$parsCitService->extractCitations($textFile, $repositoryID);
#print "$citations\n";
#print "CITEFILE: $citeFile\n";
#print "BODYFILE: $bodyFile\n";
From perldoc perlrun, about the -C switch:
Note: Since perl 5.10.1, if the -C option is used on the "#!" line, it
must be specified on the command line as well, since the standard
streams are already set up at this point in the execution of the perl
interpreter. You can also use binmode() to set the encoding of an I/O
stream.
Which is presumably what the compiler means by it being "too late".
In other words:
perl -CSD parsCit-client.pl
Because command-line options in a #! "shebang" are not passed consistently across all operating systems (see this answer), and Perl has already opened streams before parsing the script shebang, and so cannot compensate for this in some older OSs, it was decided in bug 34087 to forbid -C in the shebang. Of course, not everyone was happy with this "fix", particularly if it would have otherwise worked on their OS and they don't want to think about anything other than UTF-8.
If you think binmode() is ugly and unnecessary (and doesn't cover command-line arguments), you might like to consider the utf8::all package which has a similar effect to perl -CSDL.
Or were you using *nix, I would suggest export PERL_UNICODE="SDA" in the enclosing script to get Perl to realise it's in a UTF-8 environment.
Suppose I have a Perl script, namely mytest.pl. Can I run it by something like cat mytest.pl | perl -e?
The reason I want to do this is that I have a encrypted perl script and I can decrypt it in my c program and I want to run it in my c program. I don't want to write the decrypted script back to harddisk due to secruity concerns, so I need to run this perl script on-the-fly, all in memory.
This question has nothing to do with the cat command, I just want to know how to feed perl script to stdin, and let perl interpreter to run it.
perl < mytest.pl
should do the trick in any shell. It invokes perl and feeds the script in via the shell redirection operator <.
As pointed out, though, it seems a little unnecessary. Why not start the script with
#!/usr/bin/perl
or perhaps
#!/usr/bin/env perl
? (modified to reflect your Perl and/or env path)
Note the Useless Use of Cat Award. Whenever I use cat I stop and think whether the shell can provide this functionality for me instead.
Sometimes one needs to execute a perl script and pass it an argument. The STDIN construction perl input_file.txt < script.pl won't work. Using the tip from How to assign a heredoc value to a variable in Bash we overcome this by using a "here-script":
#!/bin/bash
read -r -d '' SCRIPT <<'EOS'
$total = 0;
while (<>) {
chomp;
#line = split "\t";
$total++;
}
print "Total: $total\n";
EOS
perl -e "$SCRIPT" input_file.txt
perl mytest.pl
should be the correct way. Why are you doing the unnecessary?
cat mytest.pl | perl
…is all you need. The -e switch expects the script as a command line argument.
perl will read the program from STDIN if you don't give it any arguments.
So you could theoretically read an encrypted file, decrypt it, and run it, without saving the file anywhere.
Here is a sample program:
#! /usr/bin/perl
use strict;
use warnings;
use 5.10.1;
use Crypt::CBC;
my $encrypted = do {
open my $encrypted_file, '<', 'perl_program.encrypted';
local $/ = undef;
<$encrypted_file>;
};
my $key = pack("H16", "0123456789ABCDEF");
my $cipher = Crypt::CBC->new(
'-key' => $key,
'-cipher' => 'Blowfish'
);
my $plaintext = $cipher->decrypt($encrypted);
use IPC::Run qw'run';
run [$^X], \$plaintext;
To test this program, I first ran this:
perl -MCrypt::CBC -e'
my $a = qq[print "Hello World\n"];
my $key = pack("H16", "0123456789ABCDEF");
my $cipher = Crypt::CBC->new(-key=>$key,-cipher=>"Blowfish");
my $encrypted = $cipher->encrypt($a);
print $encrypted;
' > perl_program.encrypted
This still won't stop dedicated hackers, but it will prevent most users from looking at the unencrypted program.