Linux/Unix Command: uniq

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uniq - remove duplicate lines from a sorted file 


uniq [OPTION]... [INPUT [OUTPUT]]  


Discard all but one of successive identical lines from INPUT (or standard input), writing to OUTPUT (or standard output).

Mandatory arguments to long options are mandatory for short options too.


prefix lines by the number of occurrences


only print duplicate lines

-D--all-repeated[=delimit-method] print all duplicate lines

delimit-method={none(default),prepend,separate} Delimiting is done with blank lines.


avoid comparing the first N fields


ignore differences in case when comparing


avoid comparing the first N characters


only print unique lines


compare no more than N characters in lines


display this help and exit


output version information and exit

A field is a run of whitespace, then non-whitespace characters. Fields are skipped before chars.  

See Also

The full documentation for uniq is maintained as a Texinfo manual. If the info and uniq programs are properly installed at your site, the command

info uniq

should give you access to the complete manual.