Hi, I have a txt file that contains 5 columns (tab delimited)...
filename col2 col3 col4 col5

I want to read in this file and output to a file only the filenames that are unique from the first file.
For example, if the txt file contains following data:
filename1 col1 col2 col3 col4 col5
filename2 col1a col2b col3c col4d col5e
filename3 col1f col2g col3h col4i col5j
filename2 col1k col2l col3m col4n col5o
filename2 col1p col2q col3r col4s col5t

I want to remove the duplicate filenames, and output the following to another file:
filename1
filename2
filename3

As I'm a beginner to Perl, can you guys provide me with any suggestions on how to approach this?
Thank you!

In reply to output unique lines only by sbp

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