uniq.1

UNIX v6源代码 这几乎是最经典的unix版本 unix操作系统设计和莱昂氏unix源代码分析都是用的该版

.th UNIQ I 12/1/72
.sh NAME
uniq \*- report repeated lines in a file
.sh SYNOPSIS
.bd uniq
[
.bd \*-udc
[ \fB+\fRn ] [ \fB\*-\fRn ]
] [ input [ output ] ]
.sh DESCRIPTION
.it 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 sort(I).
If the
.bd \*-u
flag is used,
just the lines that are not repeated
in the original file are output.
The
.bd \*-d
option specifies that
one copy of just the repeated lines is to
be written.
The normal mode output is the union of the
.bd \*-u
and
.bd \*-d
mode outputs.
.s3
The
.bd \*-c
option supersedes
.bd \*-u
and
.bd \*-d
and generates
an output report in default style
but with each line preceded by a count of the
number of times it occurred.
.s3
The
.it n
arguments specify skipping an initial portion of each line
in the comparison:
.s3
.lp +8 4
\fB\*-\fIn\fR	The first \fIn\fR 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.
.s3
.lp +8 4
\fB+\fIn\fR	The first \fIn\fR characters are ignored.
Fields are skipped before characters.
.i0
.s3
.sh "SEE ALSO"
sort (I), comm (I)
.sh BUGS