First off, using backticks is deprecated, outdated, not recommended and (in an ideal world) prohibited by law. Seriously: it is only supported for backward compatibility. Don't use it. Use the "$(...)" instead.
Second: what is your "grep" supposed to do? As you have written it, it filters the output of "ls" and i do not think this is what is intended.
Third: you have to decide either to have "grep" work in a pipeline or over a file. You can't have both, as you have written:
Fourth: This doesn't need to be an error, but i suppose it might be one. Do you really want to search for some all-caps text? If so, then all is ok, otherwise you might want to use the "-i" switch (case-insensitive search mode) for grep.
Fifth: you use awk to further work on lines found. You could probably do what your "grep" does inside awk if you use it anyways, because awk can work on select lines as well.
Hi,
I'd like to grep a variable that I saved in the program.
Like
grep '0\$variable1' file1
Does someone know what's wrong with this command?
Thanks a lot! (2 Replies)
Hi, I can't get this script to work (returns 0, should return 3):
$ cat A.lst | \
while read LINE
do
echo "$LINE"
grep -c "$LINE" B.tmp
done> > > > >
Socket
0
$
but in contrast this one works fine (returns 3 as expected):
$ LINE=Socket
$ grep -c $LINE B.tmp
3
$ (5 Replies)
Hi all,
I am trying to do a simple thing in my mind. However I am fairly new to bash. What I need to do is create a folder for each partition on each CD, and each partition has a unique name (with spaces in it, do not ask why, it is already done :confused: ) . All CD's will show up... (2 Replies)
can i grep a variable
say i have a variable var=`hostname` and I want to make an if statement like
if grep "esp-ueh" $var;then......
how can i do this
I dont want to store this variable in a file and the grep it because my script will be used at the same time on multiple stations and then that... (9 Replies)
how can I use grep with a variable to find a value?
cat data.out
Hello World
grep "Hello World" data.out
Hello World ## Value found
I want to do something like this but can't seem to get it to work any
suggestions would be appreciated.
var="Hello World"
grep $var data.out (3 Replies)
I have a pattern like:
column "5" is missing
PS: the no is in double quotes.
The number usally changes, so we use a loop to grep.
grep 'column "$number" is missing' filename.txt
But it is not working....
How to solve this? (2 Replies)
Hello,
I usually search extensively and have to date found what I've needed. However, this one's got me stumped. I need to create a variable as follow. The issue however is that upon execution, it freezes. $var1 isn't always present in usage.log and this is fine but I'd like it to continue with... (6 Replies)
I've got a file that I'm trying to grep through that looks like this:
alpha1
alpha2
alpha3
beta1
beta2
gamma5
gamma6
gamma7
gamma8
gamma9
and I want the output to only contain the line with the highest value for each, so the output I want is:
alpha3
beta2
gamma9
I also need... (11 Replies)
Hi,
I am trying to grep one variable over the other variable
Example:
i=abc
j=ab
grep $j $i
I am getting this error:
The error is due to $i being variable and not file. I know I could do it by putting the value of abc in a file
and then greping it. (1 Reply)
hi
i have a file which contains some messages counters.
below is the snippet on the file.
17-05-29::22:36:21|message|231
17-05-29::22:36:31|message|222
17-05-29::22:36:41|message|213
17-05-30::22:36:51|message|221
17-05-30::22:37:01|message|227
17-05-30::22:37:11|message|207... (5 Replies)
Discussion started by: scriptor
5 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)