32v 1m uniq
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UNIQ(1) UNIX Programmer's Manual UNIQ(1)
uniq - report repeated lines in a file
uniq [ -udc [ +n ] [ -n ] ] [ input [ output ] ]
_U_n_i_q reads the input file comparing adjacent lines. In the normal case, the second and succeeding copies of repeated lines are removed; the remainder is written on the output file. Note that repeated lines must be adjacent in order to be found; see _s_o_r_t(1). If the -u flag is used, just the lines that are not repeated in the original file are output. The -d option specifies that one copy of just the repeated lines is to be written. The normal mode output is the union of the -u and -d mode outputs.
The -c option supersedes -u and -d and generates an output report in default style but with each line preceded by a count of the number of times it occurred.
The _n arguments specify skipping an initial portion of each line in the comparison:
-_n The first _n fields together with any blanks before each are ignored. A field is defined as a string of non-space, non-tab characters separated by tabs and spaces from its neighbors.
+_n The first _n characters are ignored. Fields are skipped before characters.