Question

I have a huge system that I’m converting from a cgi to a daemon, and I need to find all the variables that end up being global (as in not declared with my $…).
They are probably intended to be scoped locally, but in Perl if you accidentally forget, it doesn’t care, but now I do.

I gotta figure the perl interpreter can tell the difference, so is there a way to get it to tell me? I could go through all the code by hand, looking for declarations, but there are thousands and thousands and thousands of lines of code in this system.

Answer 1

perldoc strict will show all variables not declared with my:

$ perl -Mstrict=vars -c -e '$x=5; my $y=7; $z=6;'
Global symbol "$x" requires explicit package name at -e line 1.
Global symbol "$z" requires explicit package name at -e line 1.
-e had compilation errors.

The same thing with a list of files:

$ perl -Mstrict=vars -c *.pl

See also strictv — how unstrict is your code?; this will give you a short summary of the variables.

Here is another way using perldoc B::Xref

$ perl -MO=Xref -e '$x=5; my $y=7; $z=6;'

... lots of verbose output

  Subroutine (main)
    Package (lexical)
      $y                i1
    Package main
      $x                1
      $z                1