C program to remove duplicate lines from a file. The text file or function must be in the same directory as the ". Simple user-interface. Jan 9, 2026 · Detailed explanation of a simple regular expression that will delete duplicate lines from a file. Portable. NOTE: Why we sorted the lines first is that uniq does not detect duplicate lines unless they are adjacent. From free lessons to IIT-M & Autodesk-certified programs, gain in-demand skills in your preferred language. Jan 31, 2026 · This is a very powerful method to find and remove duplicate files on Windows 10 and can handle large directories efficiently, but it's also risky because it involves directly deleting files. Don't reduce the file until you've indexed all of the duplicates. Suppose I have a file similar to the following: 123 123 234 234 123 345 I would like to find how many times '123' was duplicated, how many times '234' was duplicated, etc. This example illustrates simple yet clever use of capturing parentheses or backreferences. xaurwr qkkwei vfsv vixdjf hyjq qnn omuyhj rctlycvd tssfr hhh