The `uniq` command removes duplicate lines from a sorted file. It can be customized using various options, such as the `-c` option to count the number of occurrences of each repeated line.
Examples
- Remove duplicate lines from a sorted file:
uniq file.txt
- Count the number of occurrences of each repeated line:
uniq -c file.txt
- Only display duplicated lines:
uniq -d file.txt
- Ignore the first N fields in each line:
uniq -f N file.txt
- Ignore case differences:
uniq -i file.txt
- Only compare the first N characters in each line:
uniq -s N file.txt
- Only display unique lines:
uniq -u file.txt
Note: The uniq command only removes duplicate lines from a sorted file. If the file is not sorted, you need to use the sort command to sort the file first, for example, sort file.txt | uniq.