Most unix commands and functions relative to files require the input and output files to be different. For safety reasons, but also the issue of how to process a large file at the same time you are doing something to a file.
Typical solution is of the form
But, beware of automatically over-writing your original file. If you start with 1000 records, but some part of your command does not quite work as you thought, then you might end up with zero records.
I have a log file "logreport" that contains several lines as seen below:
04:20:00 /usr/lib/snmp/snmpdx: Agent snmpd appeared dead but responded to ping
06:38:08 /usr/lib/snmp/snmpdx: Agent snmpd appeared dead but responded to ping
07:11:05 /usr/lib/snmp/snmpdx: Agent snmpd appeared dead... (4 Replies)
I have a file which contains data as below:
nbk1j7o pageName=/jsp/RMBS/RMBSHome.jsf
nbk1j7o pageName=/jsp/RMBS/RMBSHome.jsf
nbk1j7o pageName=/jsp/RMBS/RMBSHome.jsf
nbk1j7o pageName=/jsp/RMBS/RMBSHome.jsf
nbk1j7o pageName=/jsp/common/index.jsf
nbk1j7o pageName=/jsp/common/index.jsf
nbk1wqe... (6 Replies)
Hello folks
I have a question for you gurus of sed or grep (maybe awk, but I would prefer the first two)
I have a file (f1) that says:
(actually, these are not numbers but md5sum, but for simplicity, let's assume these numbers.)
1
2
3
4
5And I have a file (f2) that says
1|a
1|b
1|c
2|d... (3 Replies)
Hello! i have a text file.. which contains the data as follows
i want to merge the declarations lines pertaining to one datatype in to a single line as follows
i've searched the forum for help.. but couldn't find much help.. how can i do this?? (1 Reply)
Hi,
I have a file with the lines as below:
C_10_A05_T7
C_10_A06_SP6
C_10_B05_SP6
C_10_B05_T7
C_10_B01_SP6
C_10_B01_T7
C_12_G07_SP6
C_12_G11_SP6
C_12_G11_T7
C_2_H18_T7
C_2_I02_SP6
C_2_I02_T7
C_2_I13_SP6
C_2_I17_SP6
The four segments of each line are connected by '_' symbols. I... (7 Replies)
consider i have two files
cat onlyviews1.sql
CREATE VIEW V11
AS
SELECT id,
name,
FROM
etc etc
WHERE etc etc;
CREATE VIEW V22
AS
SELECT id,
name,
FROM
etc etc
WHERE etc etc;
CREATE VIEW V33
AS (10 Replies)
Hello,
I am a java programmer but want to try unix for a purpose where I need to reduce a file using its first field.. Here is the sample data:
admin;2;0;;
admission;8;0;;
aman;1;0;;
caroline;0;4;;
cook;0;4;;
cook;2;0;;
far;0;3;;
far;1;5;;
I am explaining the dataset first. There... (5 Replies)
Hi !
I am trying to remove doubbled entrys in a textfile only between delimiters.
Like that example but i dont know how to do that with sort or similar.
input:
{
aaa
aaa
}
{
aaa
aaa
}
output:
{
aaa
}
{ (8 Replies)
URGENT HELP IS NEEDED!!
I am looking to move matching lines (01 - 07) from File1 and 77 tab the matching string from File2, to File3.txt. I am almost done but
- Currently, script is not printing lines to File3.txt in order.
- Also the matching lines are not moving out of File1.txt
... (1 Reply)
Discussion started by: High-T
1 Replies
LEARN ABOUT FREEBSD
uniq
UNIQ(1) BSD General Commands Manual UNIQ(1)NAME
uniq -- report or filter out repeated lines in a file
SYNOPSIS
uniq [-c | -d | -u] [-i] [-f num] [-s chars] [input_file [output_file]]
DESCRIPTION
The uniq utility reads the specified input_file comparing adjacent lines, and writes a copy of each unique input line to the output_file. If
input_file is a single dash ('-') or absent, the standard input is read. If output_file is absent, standard output is used for output. The
second and succeeding copies of identical adjacent input lines are not written. Repeated lines in the input will not be detected if they are
not adjacent, so it may be necessary to sort the files first.
The following options are available:
-c Precede each output line with the count of the number of times the line occurred in the input, followed by a single space.
-d Only output lines that are repeated in the input.
-f num Ignore the first num fields in each input line when doing comparisons. A field is a string of non-blank characters separated from
adjacent fields by blanks. Field numbers are one based, i.e., the first field is field one.
-s chars
Ignore the first chars characters in each input line when doing comparisons. If specified in conjunction with the -f option, the
first chars characters after the first num fields will be ignored. Character numbers are one based, i.e., the first character is
character one.
-u Only output lines that are not repeated in the input.
-i Case insensitive comparison of lines.
ENVIRONMENT
The LANG, LC_ALL, LC_COLLATE and LC_CTYPE environment variables affect the execution of uniq as described in environ(7).
EXIT STATUS
The uniq utility exits 0 on success, and >0 if an error occurs.
COMPATIBILITY
The historic +number and -number options have been deprecated but are still supported in this implementation.
SEE ALSO sort(1)STANDARDS
The uniq utility conforms to IEEE Std 1003.1-2001 (``POSIX.1'') as amended by Cor. 1-2002.
HISTORY
A uniq command appeared in Version 3 AT&T UNIX.
BSD December 17, 2009 BSD