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.
Related
Is it possible to include/source another perl script, or launch it as a "sub"?
This works, but looks ugly:
test2.pl:
print "I'm in test2.pl; args: #ARGV\n";
test.pl:
#!/usr/bin/perl
use File::Temp qw/tempdir/;
use File::Copy qw/copy/;
my $tmplib;
use lib ($tmplib = tempdir()) . (
copy("./test2.pl", "$tmplib/test2.pm") ? "" : (die "$!")
);
use test2;
x
$ ./test.pl a b c
I'm in test2.pl; args: a b c
It sounds like you want the do operator, although it also sounds like very bad design.
This is what the documentation says.
do EXPR Uses the value of EXPR as a filename and executes the contents
of the file as a Perl script.
do 'stat.pl';
is just like
eval `cat stat.pl`;
You can use do to run another Perl script in the same interpreter:
do 'test2.pl';
This will reuse the command line parameters from the outer script. To pass different parameters, you can override #ARGV locally, like:
{
local #ARGV = qw(par1 par2 par3);
do 'test2.pl';
}
Perl Code
`. /home/chronicles/logon.sh `;
print "DATA : $ENV{ID}\n";
In logon.sh , we are exporting the variable "ID" (sourcing of shell script).
Manual run
$> . /home/chronicles/logon.sh
$> echo $LOG
While I am running in terminal manually (not from script). I am getting the output. (But not working from the script)
I followed this post :
How to export a shell variable within a Perl script?
But didnt solve the problem.
Note
I am not allowed to change "logon.sh" script.
The script inside the backticks is executed in a child process. While environment variables are inherited from parent processes, the parent can't access the environment of child processes.
However, you could return the contents of the child environment variable and put it into a Perl variable like
use strict; use warnings; use feature 'say';
my $var = `ID=42; echo \$ID`;
chomp $var;
say "DATA: $var";
output:
DATA: 42
Here an example shell session:
$ cat test_script
echo foo
export test_var=42
$ perl -E'my $cmd = q(test_var=0; . test_script >/dev/null; echo $test_var); my $var = qx($cmd); chomp $var; say "DATA: $var"'
DATA: 42
The normal output is redirected into /dev/null, so only the echo $test_var shows.
It won't work.
An environment variable can't be inherited from a child process.
The environment variable can be updated in your "manual run" is because it's in the same "bash" process.
Source command is just to run every command in login.sh under current shell.
More info you can refer to: can we source a shell script in perl script
You could do something like:
#/usr/bin/perl
use strict;
use warnings;
chomp(my #values = `. myscript.sh; env`);
foreach my $value (#values) {
my ($k, $v) = split /=/, $value;
$ENV{$k} = $v;
}
foreach my $key (keys %ENV) {
print "$key => $ENV{$key}\n";
}
Well, I've find a solution, that sound nice for me: This seem robust, as this use widely tested mechanism to bind shell environment to perl (running perl) and robust library to export them in a perl variable syntax for re-injecting in root perl session.
The line export COLOR tty was usefull to ask my bash to export newer variables... This seem work fine.
#!/usr/bin/perl -w
my $perldumpenv='perl -MData::Dumper -e '."'".
'\$Data::Dumper::Terse=1;print Dumper(\%ENV);'."'";
eval '%ENV=('.$1.')' if `bash -c "
. ./home/chronicles/logon.sh;
export COLOR tty ID;
$perldumpenv"`
=~ /^\s*\{(.*)\}\s*$/mxs;
# map { printf "%-30s::%s\n",$_,$ENV{$_} } keys %ENV;
printf "%s\n", $ENV{'ID'};
Anyway, if you don't have access to logon.sh, you have to trust it before running such a solution.
Old...
There is my first post... for history purpose, don't look further.
The only way is to parse result command, while asking command to dump environ:
my #lines=split("\n",`. /home/chronicles/logon.sh;set`);
map { $ENV{$1}=$2 if /^([^ =])=(.*)$/; } #lines;
This can now be done with the Env::Modify module
use Env::Modify 'source';
source("/home/chronicles/logon.sh");
... environment setup in logon.sh is now available to Perl ...
Your Perl process is the parent of the shell process, so it won't inherit environment variables from it. Inheritance works the other way, from parent to child.
But when you run the script with backticks, as shown, the standard output of the script is returned to the Perl script. So, either modify the shell script to end with the echo $LOG statement you show, or create a new shell script that runs the login.sh and then has echo $LOG. Your Perl script would then be:
my $value = `./myscript.sh`;
print $value;
I'm unable to execute the HTML::Template function in the CGI.
I'm following a simple tutorial that I found here: http://metacpan.org/pod/HTML::Template
I created a new file on my server in the home path as test.tmpl.
I created a new file named frt.cgi ... (is that the issue here? should it be a different file extention??)
#!/usr/local/bin/perl -w
use HTML::Template;
# open the html template
my $template = HTML::Template->new(filename => '/test.html');
# fill in some parameters
$template->param(HOME => $ENV{HOME});
$template->param(PATH => $ENV{PATH});
# send the obligatory Content-Type and print the template output
print "Content-Type: text/html\n\n", $template->output;
I've modified the 1st line to reflect my host provided program path for perl. I don't know what the -w does I just know I've tried this with and without it. Also I've tried changing the code a bit like this:
use warnings;
use strict;
use CGI qw(:standard);
use HTML::Template;
I've searched...
https://stackoverflow.com/search?q=HTML%3A%3ATEMPLATE+&submit=search
https://stackoverflow.com/search?q=HTML%3A%3ATEMPLATE
https://stackoverflow.com/search?q=HTML%3A%3ATEMPLATE+PERL&submit=search
Yet I still do not see the answer.
I even searched google for .TMPL Encoding because I thought there may be some special type needed. Please help.
If you look in your server logs, you'll probably see an error message along the lines of:
HTML::Template->new() : Cannot open included file /test.html : file not found.
You need to provide the path on the file system, not a URI relative to the generated document.
First, you likely specified the wrong path - change /test.html to test.html.
Also, it is possible that there is no $ENV{HOME} variable in your system so set up flag die_on_bad_params to 0:
my $template = HTML::Template->new(
filename => 'test.html',
die_on_bad_params => 0,
);
Also, don't forget to mark your Perl file as executable by chmod 755.
Option -w makes Perl to enable warnings, so there is no point to write use warnings; afterwards.
You can check what Perl command line options do by using module B::Deparse, like this ($^W variable disables/enables warnings):
perl -w -MO=Deparse -e "print;"
This would print:
BEGIN { $^W = 1; }
print $_;
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 $ft "Hello, world.\n";
I have a shell script that does nothing but set a bunch of environment variables:
export MYROOTDIR=/home/myuser/mytools
export PATH=$MYROOTDIR/bin:$PATH
export MYVERSION=0.4a
I have a perl script, and I want the perl script to somehow get the perl script to operate with the env vars listed in the shell script. I need this to happen from within the perl script though, I do not want the caller of the perlscript to have to manually source the shellscript first.
When trying to run
system("sh myshell.sh")
the env vars do not "propagate up" to the process running the perl script.
Is there a way to do this?
To answer this question properly, I need to know a bit more.
Is it okay to actually run the shell script from within the perl script?
Are the variable assignments all of the form export VAR=value (i.e. with fixed assignments, no variable substitutions or command substitutions)?
Does the shell script do anything else but assign variables?
Depending on answers to these, options of different complexity exist.
Thanks for the clarification. Okay, here's how to do it. Other than assigning variables, your script has no side effects. This allows to run the script from within perl. How do we know what variables are exported in the script? We could try to parse the shell script, but that's not the Unix way of using tools that do one thing well and chain them together. Instead we use the shell's export -p command to have it announce all exported variables and their values. In order to find only the variables actually set by the script, and not all the other noise, the script is started with a clean environment using env -i, another underestimated POSIX gem.
Putting it all together:
#!/usr/bin/env perl
use strict;
use warnings;
my #cmd = (
"env", "-i", "PATH=$ENV{PATH}", "sh", "-c", ". ./myshell.sh; export -p"
);
open (my $SCRIPT, '-|', #cmd) or die;
while (<$SCRIPT>) {
next unless /^export ([^=]*)=(.*)/;
print "\$ENV{$1} = '$2'\n";
$ENV{$1} = $2;
}
close $SCRIPT;
Notes:
You need to pass to env -i all environment your myshell.sh needs, e.g. PATH.
Shells will usually export the PWD variable; if you don't want this in your perl ENV hash, add next if $1 eq 'PWD'; after the first next.
This should do the trick. Let me know if it works.
See also:
http://pubs.opengroup.org/onlinepubs/009695399/utilities/export.html
http://pubs.opengroup.org/onlinepubs/009695399/utilities/env.html
Try Shell::Source.
You can set the environment variables inside the BEGIN block.
BEGIN block is executed before the rest of the code, setting the environment variables in this block makes them visible to the rest of the code before it is compiled and run.
If you have any perl modules to 'use' based on the enviornment settings, BEGIN block makes it possible.
Perl uses a special hash %ENV to maintain the environment variables.
You can modify the contents of this hash to set the env variables.
EXAMPLE :
BEGIN
{
$ENV { 'MYROOTDIR' } = '/home/myuser/mytools';
$ENV { 'PATH' } = "$ENV{ 'MYROOTDIR' }/bin:$ENV{ 'PATH' }";
}
Wouldn't it be easier for a shell script to set the variables, and then call the perl program?
i.e.:
run.sh:
#!/bin/sh
export MYROOTDIR=/home/myuser/mytools
export PATH=$MYROOTDIR/bin:$PATH
export MYVERSION=0.4a
./program.pl
This can now be done with Env::Modify with few changes to your existing code.
use Env::Modify 'system';
...
system("sh myshell.sh");
print $ENV{MYROOTDIR}; # "/home/myuser/mytools"
or if all your shell script does is modify the environment, you can use the source function
use Env::Modify `source`;
source("myshell.sh");
print $ENV{MYVERSION}; # "0.4a"