Search Commands

uniq Linux Command

Reports or filters out repeated lines in a sorted file.

What does uniq do?

Reports or filters out repeated lines in a sorted file.

uniq [options] file

sort file.txt | uniq -c

How do I remove duplicate lines with uniq?

Use `sort file | uniq` to remove duplicates. uniq only removes consecutive duplicates, so the file must be sorted first.

How do I count occurrences with uniq?

Use `sort file | uniq -c` to count how many times each line appears. The count is prepended to each line.

How do I show only duplicate lines?

Use `sort file | uniq -d` to display only lines that appear more than once.

How do I show only unique lines?

Use `sort file | uniq -u` to display only lines that appear exactly once (no duplicates).

How do I ignore case when finding duplicates?

Use `sort file | uniq -i` to ignore case. 'Hello' and 'hello' will be treated as duplicates.

How do I skip fields when comparing lines?

Use `uniq -f 2 file` to skip the first 2 fields when comparing lines. Useful for ignoring timestamps or prefixes.

How do I count unique words in a file?

Use `cat file | tr ' ' '\n' | sort | uniq -c` to split words, sort them, and count occurrences.

How do I sort and count log entries?

Use `sort access.log | uniq -c | sort -rn` to count and sort log entries by frequency, most common first.

Sorts lines of text files alphabetically or numerically.

Extracts specific columns/fields from each line of a file.

Stream editor for filtering and transforming text (find/replace, insert, delete).

Translates, deletes, or squeezes characters from standard input.

Powerful text processing language for pattern scanning and data extraction.

Builds and executes command lines from standard input (useful with pipes).