Find and remove duplicate lines in a text file

Find and Remove Duplicate Lines in a Text File
- Python for Integrated Circuits -
- An Online Book -

Python for Integrated Circuits http://www.globalsino.com/ICs/

Chapter/Index: Introduction | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Appendix

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Remove duplicate lines in a text file. code:
Move to some position and click mouse at some position
Input:

Output (but keeps one line for each duplicated line):

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Find duplicate lines in a text file. code:
Move to some position and click mouse at some position
Input:

Output:

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