If there is some question of what the shell is doing to your command line, you might want to try the capturex() subroutine in IPC::System::Simple. This subroutine bypasses the shell, so you don't have to worry about sanitizing metacharacters, and your command sees exactly the arguments you pass it.

IPC::System::Simple is not a core module, so you would have to install it yourself, or get a friendly system administrator (if any) to do it for you.

The recommendation above to put the arguments in an array may well have merit as a troubleshooting step, so you can print them before the command. But in your specific case the qw{...} construction is of limited usefulness because it does not interpolate. You would have to build the array with something like

my @args = ( 'command', "--arg1=$num1", '--arg2=file.log', ... "-argLa
+st=$numLast" );
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. The switching between quote types in the example is a stylistic thing, since "" interpolates and '' does not, and you should do whatever your local coding standards say.