uniq -- remove duplicate lines from a sorted file


uniq is as specified in the SUS but with differences as listed below.

LSB Deprecated Differences

The behaviors specified in this section are expected to disappear from a future version of the LSB; applications should only use the non-LSB-deprecated behaviors.


is equivalent to -c.


is equivalent to -d.

-D, --all-repeated

prints all duplicate lines.


is equivalent to -f fields.

-i, --ignore-case

ignores differences in case when comparing.


is equivalent to -s.


is equivalent to -u.

-w, --check-chars=N

compares no more than N characters in lines.


outputs version information and exits.