$ perl -Mre=debug -le " $_=q{fakesite.com/f/files-url/blah.png}; if(m{fakesite.com.*}g){ warn 1; if(/files-url/g){ die 2
 }} "
Compiling REx "fakesite.com.*"
Final program:
   1: EXACT <fakesite> (4)
   4: REG_ANY (5)
   5: EXACT <com> (7)
   7: STAR (9)
   8:   REG_ANY (0)
   9: END (0)
anchored "fakesite" at 0 (checking anchored) minlen 12
Compiling REx "files-url"
Final program:
   1: EXACT <files-url> (5)
   5: END (0)
anchored "files-url" at 0 (checking anchored isall) minlen 9
Guessing start of match in sv for REx "fakesite.com.*" against "fakesite.com/f/files-url/blah.png"
Found anchored substr "fakesite" at offset 0...
Guessed: match at offset 0
Matching REx "fakesite.com.*" against "fakesite.com/f/files-url/blah.png"
   0 <> <fakesite.c>         |  1:EXACT <fakesite>(4)
   8 <esite> <.com/f/fil>    |  4:REG_ANY(5)
   9 <site.> <com/f/file>    |  5:EXACT <com>(7)
  12 <e.com> </f/files-u>    |  7:STAR(9)
                                  REG_ANY can match 21 times out of 2147483647...
  33 <url/blah.png> <>       |  9:  END(0)
Match successful!
1 at -e line 1.
Freeing REx: "fakesite.com.*"
Freeing REx: "files-url"

$
$ perl -Mre=debug -le " $_=q{fakesite.com/f/files-url/blah.png}; if(m{fakesite.com.*}){ warn 1; if(/files-url/){ die 2 }
} "
Compiling REx "fakesite.com.*"
Final program:
   1: EXACT <fakesite> (4)
   4: REG_ANY (5)
   5: EXACT <com> (7)
   7: STAR (9)
   8:   REG_ANY (0)
   9: END (0)
anchored "fakesite" at 0 (checking anchored) minlen 12
Compiling REx "files-url"
Final program:
   1: EXACT <files-url> (5)
   5: END (0)
anchored "files-url" at 0 (checking anchored isall) minlen 9
Guessing start of match in sv for REx "fakesite.com.*" against "fakesite.com/f/files-url/blah.png"
Found anchored substr "fakesite" at offset 0...
Guessed: match at offset 0
Matching REx "fakesite.com.*" against "fakesite.com/f/files-url/blah.png"
   0 <> <fakesite.c>         |  1:EXACT <fakesite>(4)
   8 <esite> <.com/f/fil>    |  4:REG_ANY(5)
   9 <site.> <com/f/file>    |  5:EXACT <com>(7)
  12 <e.com> </f/files-u>    |  7:STAR(9)
                                  REG_ANY can match 21 times out of 2147483647...
  33 <url/blah.png> <>       |  9:  END(0)
Match successful!
1 at -e line 1.
Guessing start of match in sv for REx "files-url" against "fakesite.com/f/files-url/blah.png"
Found anchored substr "files-url" at offset 15...
Starting position does not contradict /^/m...
Guessed: match at offset 15
2 at -e line 1.
Freeing REx: "fakesite.com.*"
Freeing REx: "files-url"

$