More Arguments

[joaming]

Hi, I am new to Perl, learning how to parse a linux log file. So, I grep sth from the log, serving as input to m parse script and print the result to a proper format.

[linux host] $ grep "Something" sample.log | perl myParser.pl 

my $line;
foreach $line (<>) {
...
}

This works fine, but I would like to supply more parameter to my perl script to determine the format style, eg.

$ grep "Something" sample.log | perl myParser.pl VERTICAL

will print the result vertically,

$ grep "Something" sample.log | perl myParser.pl COLUMN

will print the result in columnized format.

I tried to capture it by $ARGV[0], $ARGV1, but still failed. Please kindly help

More, i did a simple test

#!/usr/bin/perl
use strict;
my $param0 = $ARGV[0];
my $line;

print "\nFirst Arguement is : $param0";

foreach $line (<>) {
...
}

$ grep "Name=" sample.log | perl SimpleTest.pl VERTICAL

Can't open VERTICAL: No such file or directory at SimpleTest.pl line 1
+1.
First Arguement is : VERTICAL

Then , it just stopped and not execute the foreach loop

[Athanasius]

Hello joaming,

To get the syntax right, you’ll need to study perlop#I/O Operators:

The null filehandle <> is special: it can be used to emulate the behavior of sed and awk, .... Input from <> comes either from standard input, or from each file listed on the command line. Here's how it works: the first time <> is evaluated, the @ARGV array is checked, and if it is empty, $ARGV[0] is set to "-", which when opened gives you standard input....


By trial and error, I found the following (on Windows), which seems to do what you’re looking for:

14:17 >echo Hello| perl -wE "$x = <>; chomp $x; $y = $ARGV[0]; say qq[
+>$x $y<];" - world
>Hello world<

14:17 >

The call to <> finds - as the first argument on the command line and so reads from standard input, which is Hello\n. After this, @ARGV is apparently reset. I haven’t found that behaviour documented (yet).

Anyway, hope that helps,

[joaming]

Thank you. I still have a long road to walk on Perl, lol

[choroba]

Don't use the bare diamond <> if you want to handle arguments yourself and read from the standard input. Use <STDIN> instead:

echo input | perl -we 'print "ARGS: @ARGV\n"; print while <STDIN>' fil
+e.txt arg2

[stevieb]

Hey, joaming, welcome to the Monastery.

Could you please provide some of your input data, expected output and a bit more of your code? This will help us determine where we can improve on what you've already got.

-stevieb

[joaming]

I am sorry I didn't address what I encountered at the first place accurately. Now I updated with a SimpleTest.pl, I expect the code continue to run and enter the foreach loop, but it didn't.

[parv]

Show your code where you try to use @ARGV & fail.

[QuillMeantTen]

You can keep the code you wrote and just use xargs that way you will call your script multiple times with just one argument
Update: oops my bad I misread what you wrote, please disregard