this command searches value 5000 in only 6th column from provided file where pipe ( | )is delimiter which separate columns... can some one plz explain me what
actually does..?
Last edited by jim mcnamara; 12-23-2012 at 02:53 PM..
Hi,
Could you please explain me the below statement -- phrase wise.
sed -e :a -e '$q;N;'$cnt',$D;ba' abc.txt > xyz.txt
if suppose $cnt contains value: 10
it copies last 9 lines of abc.txt to xyz.txt
why it is copying last 9 rather than 10.
and also what is ba and $D over there in... (4 Replies)
Hello:
I'm a very newbee at UNIX/AIX.
What i want to do is to tail a file from the bottom until a certain string is found and write all the lines after the found string to another file.
I've tried out a lot of combination with tail and grep but doesn't find the good one.
Could someone help... (4 Replies)
Hello!
I want to read a file line by line and have each line in a variable. I have found the following code.
#!/bin/bash
exec 3< data
while read <&3
do echo "The number is $REPLY"
a.out "$REPLY"
done
exec 3>&-
I don't understand the use of exec and its arguments, though having read... (3 Replies)
hi this is the output of showrev command from my sun blade 150 machine.
bash-3.00# showrev
Hostname: u15_9
Hostid: 83685284
Release: 5.10
Kernel architecture: sun4u
Application architecture: sparc
Hardware provider: Sun_Microsystems
Domain: sun.com
Kernel version: SunOS 5.10... (1 Reply)
Hi all,
I need some urgent help with grep.
I'm simply trying to extract the current date from the syslog file, which is "Oct 6" and then grepping this and output the messages to a new log file.
See the below commands and output, even though the log file is created, it is created with all the... (8 Replies)
Hi all,
I'm very new to UNIX. I have got a coding, where i dont understand the below part. Could someone please explain it in detail?
awk 'NR > 1; NR == 1 { S = $0 } END { print S }' $textfile.bak > $textfile
could someone explain what
awk 'NR > 1; NR == 1 { S = $0 } END { print S }'
... (1 Reply)
Could someone explain why Python 3.1 errors out below? Do I need an additional module that's not required in 3.2 perhaps? I need to use 3.1 as it's the version available on a server I am using.
Python 3.2.1rc1 (default, May 18 2011, 11:01:17)
on linux2
Type "help", "copyright", "credits"... (0 Replies)
I had gone through..google search.....and unix user post.......where I found so many ways of accessing files..... suppose if I am having 4 files, each file is having 3 columns, and I want to use each field of each column, then how can I use it.. how can I create array for each file's each column,... (8 Replies)
Hey Friends, its me again! :o
I was asked to create a script that would go into our backup directories and delete/purge anything in the directory after a certain amount of days, normally I would be able to write something up that goes to the directory finds it and deletes it.
cd... (12 Replies)
#!/bin/bash
n=$l; typeset -a v
x=$(< input.dat)
check(){
if; then
sed 's/Test/Proc/g' file.sh >fl.sh
else
exit 13
fi
}
check $n
while ; do
x=`expr $x -l`
v=$x
done
less fi.sh l>/dev/null&& echo yes || exit 1
echo v= ${v
}
exit 0
I have file.sh and input.dat in the current... (3 Replies)
Discussion started by: bananasprite
3 Replies
LEARN ABOUT DEBIAN
poe::filter::grep
POE::Filter::Grep(3pm) User Contributed Perl Documentation POE::Filter::Grep(3pm)NAME
POE::Filter::Grep - select or remove items based on simple rules
SYNOPSIS
#!perl
use POE qw(
Wheel::FollowTail
Filter::Line Filter::Grep Filter::Stackable
);
POE::Session->create(
inline_states => {
_start => sub {
my $parse_input_as_lines = POE::Filter::Line->new();
my $select_sudo_log_lines = POE::Filter::Grep->new(
Put => sub { 1 },
Get => sub {
my $input = shift;
return $input =~ /sudo[d+]/i;
},
);
my $filter_stack = POE::Filter::Stackable->new(
Filters => [
$parse_input_as_lines, # first on get, last on put
$select_sudo_log_lines, # first on put, last on get
]
);
$_[HEAP]{tailor} = POE::Wheel::FollowTail->new(
Filename => "/var/log/system.log",
InputEvent => "got_log_line",
Filter => $filter_stack,
);
},
got_log_line => sub {
print "Log: $_[ARG0]
";
}
}
);
POE::Kernel->run();
exit;
DESCRIPTION
POE::Filter::Grep selects or removes items based on simple tests. It may be used to filter input, output, or both. This filter is named
and modeled after Perl's built-in grep() function.
POE::Filter::Grep is designed to be combined with other filters through POE::Filter::Stackable. In the "SYNOPSIS" example, a filter stack
is created to parse logs as lines and remove all entries that don't pertain to a sudo process. (Or if your glass is half full, the stack
only selects entries that DO mention sudo.)
PUBLIC FILTER METHODS
In addition to the usual POE::Filter methods, POE::Filter::Grep also supports the following.
new
new() constructs a new POE::Filter::Grep object. It must either be called with a single Code parameter, or both a Put and a Get parameter.
The values for Code, Put, and Get are code references that, when invoked, return true to select an item or false to reject it. A Code
function will be used for both input and output, while Get and Put functions allow input and output to be filtered in different ways. The
item in question will be passed as the function's sole parameter.
sub reject_bidoofs {
my $pokemon = shift;
return 1 if $pokemon ne "bidoof";
return;
}
my $gotta_catch_nearly_all = POE::Filter::Grep->new(
Code => &reject_bidoofs,
);
Enforce read-only behavior:
my $read_only = POE::Filter::Grep->new(
Get => sub { 1 },
Put => sub { 0 },
);
modify
modify() changes a POE::Filter::Grep object's behavior at run-time. It accepts the same parameters as new(), and it replaces the existing
tests with new ones.
# Don't give away our Dialgas.
$gotta_catch_nearly_all->modify(
Get => sub { 1 },
Put => sub { return shift() ne "dialga" },
);
SEE ALSO
POE::Filter for more information about filters in general.
POE::Filter::Stackable for more details on stacking filters.
BUGS
None known.
AUTHORS & COPYRIGHTS
The Grep filter was contributed by Dieter Pearcey. Documentation is provided by Rocco Caputo.
Please see the POE manpage for more information about authors and contributors.
perl v5.14.2 2012-05-15 POE::Filter::Grep(3pm)