Tribblix: manual page: uniq.1

UNIQ(1) User Commands UNIQ(1)

NAME

uniq - report or filter out repeated lines in a file

SYNOPSIS

/usr/bin/uniq
/usr/bin/uniq [-c | -d | -u] [-f fields] [-s char]
[input_file [output_file]]

/usr/bin/uniq [-c | -d | -u] [-n] [+ m] [input_file [output_file]]

ksh93
uniq [-cdiu] [-D[delimit]] [-f fields] [-s chars] [-w chars]
[input_file [output_file]]

uniq [-cdiu] [-D[delimit]] [-n] [+m] [-w chars] [input_file [output_file]]

DESCRIPTION

/usr/bin/uniq
The uniq utility reads an input file comparing adjacent lines and
writes one copy of each input line on the output. The second and
succeeding copies of repeated adjacent input lines are not written.

Repeated lines in the input are not detected if they are not
adjacent.

ksh93
The uniq built-in in ksh93 is associated with the /bin or /usr/bin
path. It is invoked when uniq is executed without a pathname prefix
and the pathname search finds a /bin/uniq or /usr/bin/uniq
executable.

uniq reads an input, comparing adjacent lines, and writing one copy
of each input line on the output. The second and succeeding copies of
the repeated adjacent lines are not written.

If output_file is not specified, uniq writes to standard output. If
input_file is not specified, or if input_file is -, uniq reads from
standard input, and the start of the file is defined as the current
offset.

OPTIONS

/usr/bin/uniq
The following options are supported by /usr/bin/uniq:

-c
Precedes each output line with a count of the number of
times the line occurred in the input.

-d
Suppresses the writing of lines that are not repeated in
the input.

-f fields
Ignores the first fields fields on each input line when
doing comparisons, where fields is a positive decimal
integer. A field is the maximal string matched by the
basic regular expression:

[[:blank:]]*[^[:blank:]]*

If fields specifies more fields than appear on an input
line, a null string is used for comparison.

+m
Equivalent to -s chars with chars set to m.

-n
Equivalent to -f fields with fields set to n.

-s chars
Ignores the first chars characters when doing
comparisons, where chars is a positive decimal integer.
If specified in conjunction with the -f option, the
first chars characters after the first fields fields is
ignored. If chars specifies more characters than remain
on an input line, a null string is used for comparison.

-u
Suppresses the writing of lines that are repeated in the
input.

ksh93
The following options are supported by the uniq built-in command is
ksh93:

-c
--count
Outputs the number of times each line
occurred along with the line.

-d
--repeated | duplicates
Outputs only duplicate lines.

-D
--all-repeated[=delimit]
Outputs all duplicate lines as a group
with an empty line delimiter specified by
delimit.

Specify delimit as one of the following:

none
Do not delimit duplicate
groups.

prepend
Prepend an empty line before
each group.

separate
Separate each group with an
empty line.

The value for delimit can be omitted. The
default value is none.

-f
--skip-fields=fields
Skips over fields number of fields before
checking for uniqueness. A field is the
minimal string matching the BRE
[[:blank:]]*[^[:blank:]]*.

-i
--ignore-case
Ignore case in comparisons.

+m
Equivalent to the -s chars option, with
chars set to m.

-n
Equivalent to the -f fields option, with
fields set to n.

-s
--skip-chars=chars
Skips over chars number of characters
before checking for uniqueness.

If specified with the -f option, the
first chars after the first fields are
ignored. If the chars specifies more
characters than are on the line, an empty
string is used for comparison.

-u
--uniq
Outputs unique lines.

-w
--check-chars=chars
Skips over any specified fields and
characters, then compares chars number of
characters.

OPERANDS

The following operands are supported:

input_file
A path name of the input file. If input_file is not
specified, or if the input_file is -, the standard
input is used.

output_file
A path name of the output file. If output_file is not
specified, the standard output is used. The results
are unspecified if the file named by output_file is
the file named by input_file.

EXAMPLES

Example 1: Using the uniq Command

The following example lists the contents of the uniq.test file and
outputs a copy of the repeated lines.

example% cat uniq.test
This is a test.
This is a test.
TEST.
Computer.
TEST.
TEST.
Software.

example% uniq -d uniq.test
This is a test.
TEST.
example%

The next example outputs just those lines that are not repeated in
the uniq.test file.

example% uniq -u uniq.test
TEST.
Computer.
Software.
example%

The last example outputs a report with each line preceded by a count
of the number of times each line occurred in the file:

example% uniq -c uniq.test
2 This is a test.
1 TEST.
1 Computer.
2 TEST.
1 Software.
example%

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment
variables that affect the execution of uniq: LANG, LC_ALL, LC_CTYPE,
LC_MESSAGES, and NLSPATH.

EXIT STATUS

The following exit values are returned:

0
Successful completion.

>0
An error occurred.

ATTRIBUTES