The uniq command can count and print the number of repeated lines. Just like duplicate lines, we can filter unique lines (non-duplicate lines) as well and can also ignore case sensitivity. We can skip fields and characters before comparing duplicate lines and also consider characters for filtering lines.

Why uniq is used in Linux?

The uniq command in Linux is a command line utility that reports or filters out the repeated lines in a file. In simple words, uniq is the tool that helps to detect the adjacent duplicate lines and also deletes the duplicate lines.

What does uniq do in Unix?

uniq is a utility command on Unix, Plan 9, Inferno, and Unix-like operating systems which, when fed a text file or STDIN, outputs the text with adjacent identical lines collapsed to one, unique line of text.