If you see a loop like 
while (<>){
 ...
}

[download]
then it means that the script is reading from STDIN (standard input). You now need to find out how to compose a command line that passes your file on STDIN to the perl script, which is a nice little exercise... :)
One of the solutions posted here used a DATA block at the end of the script, i.e. there is a signal to tell the perl interpreter that the rest of the file is not Perl code but data and the while loop reads from the data block line by line instead of STDIN.

In reply to Re^3: max and min values in 3-column file by tospo
in thread max and min values in 3-column file by perldummie

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