uniq

Output the unique lines from the given input or file. Since it does not detect repeated lines unless they are adjacent, we need to sort them first.

• Display each line once:

sort {{file}} | uniq

• Display only unique lines:

sort {{file}} | uniq -u

• Display only duplicate lines:

sort {{file}} | uniq -d

• Display number of occurrences of each line along with that line:

sort {{file}} | uniq -c

• Display number of occurrences of each line, sorted by the most frequent:

sort {{file}} | uniq -c | sort -nr