I’m going to repeat the excellent advice you have already heard. :P

Dealing with the FS and IO is drastically slower than all of these approaches. So you should not, arguably, be choosing by speed or cleverness but for legibility and future maintenance. Choosing by speed will not be noticed unless you are processing billions of files daily. I adore and use features like string incrementing in Perl. I probably wouldn’t do it at work, maybe, because it’s pretty idiomatic. That said, it’s also the fastest–

            Rate      glob    unpack     split  n_nested   sprintf inc
+rement
glob      78.0/s        --      -23%      -23%      -85%      -87%    
+  -90%
unpack     101/s       29%        --       -0%      -80%      -84%    
+  -87%
split      101/s       30%        0%        --      -80%      -84%    
+  -87%
n_nested   513/s      558%      409%      407%        --      -18%    
+  -36%
sprintf    623/s      698%      517%      515%       21%        --    
+  -22%
increment  797/s      922%      690%      687%       55%       28%    
+    --

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In reply to Re^5: looping efficiency by Your Mother
in thread looping efficiency by Anonymous Monk

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