I have a file with the below data, i would like to remove the end blank lines with no data. I used the below commands but could not able to succeed, could you please shed some light.
Commands Used:
sed '/^$/d' input.txt > output.txt
grep -v '^$' input.txt > output.txt
input.txt file... (5 Replies)
I have a .xml file, where i need some output. The xml file is like:
Code:
<?******?></ddddd><sssss>234</dfdffsdf><sdhjh>534</dfdfa>.........
/Code
I need the output like:
code
234
534
.
.
.
/code
How can i do it? (5 Replies)
Hi,
I got a log file and I want to grep out a list of unwanted line which are IP's.
Basiclly I want everything ecxept the ip's from my list.
If I do a
while read line
do
grep -v $ip_from_my_list logfile
done <ip_list
it just grep's one IP at a time and repeats. :(
Thanks for... (3 Replies)
I am running a grep query for searching a pattern, and the output is quite huge. I want only the last 200 lines to be displayed, and I am not sure if tail will do the trick (can tail read from std in/out instead of files?).
Please help me out. (1 Reply)
Ok, i have a .kml file that that i want to trim down and get rid of the rubbish from. its formatted like so:
<Placemark>
<name><!]></name>
<description><!</b><br/>Frequency: <b>2437</b><br/>Timestamp: <b>1304892397000</b><br/>Date: <b>2011-05-08... (11 Replies)
Thanks everyone. I got that problem solved.
I require one more help here. (Yes, UNIX definitely seems to be fun and useful, and I WILL eventually learn it for myself. But I am now on a different project and don't really have time to go through all the basics. So, I will really appreciate some... (6 Replies)
Hi.
I need to filter lines based upon matches in multiple tab-separated columns. For all matching occurrences in column 1, check the corresponding column 4. IF all column 4 entries are identical, discard all lines. If even one entry in column 4 is different, then keep all lines.
How can I... (5 Replies)
Hello,
I need a little help with the following:
I'm using AWK to read input from a comma-seperated value file, and only printing certain fields like so:
awk -F "," '{print $1,$3,$6}' /list.csv | tail -1
Which outputs the following:
server1 APPID OS
I run into a problem... (8 Replies)
I have a file contains data with non-printing characters. i have used cat -v filename to display whole data with non-printing characters also.
However, i need lines with non-printing characters into seperate file. My file is huge and looks like i have to manully find lines using cat -v filename |... (3 Replies)
Discussion started by: JSKOBS
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)