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Remove duplicate lines with uniq

After sorting a file you will often find that some duplicate data, or you may be given various lists that need deduping. sort and uniq will quickly and easily remove duplicates, lsit only the dupilcates or only the unique data.

sort myfile.txt | uniq

List only the unique lines: sort myfile.txt | uniq -u

List only the duplicate lines: sort myfile.txt | uniq -d

Get a count of the number of lines by adding the -c option.

sort myfile.txt | uniq -uc

sort myfile.txt | uniq -dc

Skip fields: uniq -f 3 mylogfile. this could be useful with log files to skip the time stamp data

Skip characters. uniq -s 30 myfile.txt. Skip the first 30 characters

Compare characters. uniq -w 30 myfile.txt. Compare the first 30 characters

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