Use the same perl script with several different variables
I'm new to perl and have to create these files for my job. I have a script that I can run that will create the file, but I have to manually pass the variables to it. It is dumb and it takes a lot of time. I want to be able to pass the existing perl script a set of variables (the same variables with different values) over and over again, until it runs through them.
Basically, I want to keep a file with the variables:
$variable1
$variable2
$variable3
run script with these > output to a file
$variable1
$variable2
$variable3
run script with these > output to a file
so say you put your variables in space-delimited lines in a file name 'in.txt'. The content of this file for example is:
Code:
abc def ghi
jkl mno pqr
you could invoke your script 'script.pl' like this:
Code:
script.pl in.txt out.txt
as you may know, in.txt is passed into the script in the default array ARGV.
inside your script, you would have something like this, then, to create file handles to open the input file, and a second arg for the output file
Code:
open FHIN,"<$ARGV[0]";
open FHOUT, ">$ARGV[1]";
then you would read the input file line by line, splitting each line on spaces into an array, to pass to your processing function for output:
Code:
#!/usr/bin/perl
# the function you will execute with your vars
sub proc_array
{
# open the output filehandle
open FHOUT, ">ARGV[1]";
#iterate over the array you pass to the function
foreach my $var (@_)
{
# here it just prints the value and a newline
# but you would be doing something more interesting
print FHOUT $var."\n"
}
# close the output filehandle
close FHOUT;
}
#open the file handle
open FHIN, $ARGV[0];
#iterate over each line in the file
foreach my $line (<FHIN>)
{
# split the space-delimited var strings and store each var in an array
my @vars = split(/\s/,$line);
# pass the array to your processing function
proc_array(@vars);
}
# close the filehandle when done
close FHIN;
the output of the script in this example is:
Code:
abc
def
ghi
jkl
mno
pqr
if you want to output to multiple files, you could either pass in multiple args, or name your file with timestamps or something else programmatically.
Last edited by varontron; 10-03-2009 at 12:27 AM..
I've tested this and it works, but I'm not able to put variables in my input file and have them read as variables. I'm not sure if that makes sense, but if I declare my variables in my input file, the other script doesn't recognize them as a variable, only a string.
If you're declaring variables in the first script and then calling the second from it, you need to use some sort of persistent memory, which is probably way overcomplicated. the second perl script has no knowledge of the memory used by it's caller.
alternatively you want to declare vars in the second script to hold the vals you need, and pass those values from the first script to it. you can do this through arguments, pipes, files, etc.
I have reviewed many examples on-line about running another process (either PERL or shell command or a program), but do not find any usefull for my needs way. (Reviewed and not useful the system(), 'back ticks', exec() and open())
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