uniq

Output the unique lines from a input or file. Since it does not detect repeated lines unless they are adjacent, we need to sort them first. More information: https://www.gnu.org/software/coreutils/uniq.

• Display each line once:

sort path/to/file | uniq

• Display only unique lines:

sort path/to/file | uniq -u

• Display only duplicate lines:

sort path/to/file | uniq -d

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

sort path/to/file | uniq -c

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

sort path/to/file | uniq -c | sort -nr