4.1cBSD/usr/man/man1/uniq.1

.TH UNIQ 1  "10 February 1983"
.SH NAME
uniq \- report repeated lines in a file
.SH SYNOPSIS
.B uniq
[
.B \-udc
[
.BR + n
] [
.BR \- n
]
] [ input [ output ] ]
.SH DESCRIPTION
.I Uniq
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
.IR  sort (1).
If the
.B \-u
flag is used, just the lines that are not repeated
in the original file are output.  The
.B \-d
option specifies that one copy of just the repeated lines is to be written.
The normal mode output is the union of the
.B \-u
and
.B \-d
mode outputs.
.PP
The
.B \-c
option supersedes
.B \-u
and
.B \-d
and generates an output report in default style
but with each line preceded by a count of the number of times it occurred.
.PP
The
.I n
arguments specify skipping an initial portion of each line in the comparison:
.TP 8
.BI \- n
The first
.IR 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.
.TP 8
.BI + n
The first
.IR n 
characters are ignored.  Fields are skipped before characters.
.PP
.SH "SEE ALSO"
sort(1), comm(1)
.SH MESSAGES
.IP "cannot open \fIfilename\fP" 10
.br
\fIUniq\fP cannot access the input filename specified by \fIfilename\fP.
Check that you have spelled the name correctly, or that you have
permission to access that file.
.IP "cannot create \fIfilename\fP" 10
.br
\fIUniq\fP cannot creat the output filename specified by \fIfilename\fP.
Check that you have write permission in the directory in which
\fIuniq\fP is trying to create the file.