uniq - Remove Adjacent Duplicate Lines

The uniq command is used to remove adjacent duplicate lines from a file. It will only remove lines that are duplicates of the immediately preceding line. If there are duplicates that are not adjacent to each other, they will not be removed.

The basic syntax for the uniq command is as follows:
uniq [OPTIONS] [IN_FILE] [OUT_FILE] .

Here are some common options for the uniq command:

• -d : Display only duplicate lines, excluding unique lines.
• -u : Display only unique lines, excluding duplicate lines.
• -c : Display the count of each duplicate line.
• -i : Ignore case while comparing lines.
• -f N : Ignore the first N fields (whitespace-separated) of each line before comparing.
• -s N : Skip the first N characters of each line before comparing.
• -w N : Compare only the first N characters of each line.

n the above test, the line "aaa" appeared three times, but it was only removed when it was adjacent to the previous line. The non-adjacent duplicate line was not removed.

For more uniq options and examples, you can refer to the provided link.