It oughta work. Seems to work here with this test scenario. Similar to previous response, two likely causes would be "file is empty" or "grep didn't find anything".
Hi,
I'm quite new to scripting and I want to modify following line of an existing script:
MYVAR=`subst |grep 'L:\\\:' | sed -e 's/.*\\\//'`;
What I have to do is to use the content of a variable instead of the constant expression 'L:\\\:' as the grep string to be matched.
Assuming I already... (5 Replies)
I have a variable A
echo $A
5060
I am exporting the value X,Y,Z and it id fetching right thing and When I run
C=`${X} -l ${Y} ${Z} "trap '' INT;. ~/.profile >/dev/null 2>/dev/null; netstat -na | grep \$A`"
here it is going to same directory and also running netstat -na | grep 5060
... (4 Replies)
I am trying to cat a file and then grep that file for a number. I can do it fine on other files but this particular file will not do anything. I tried running it on an older file from the same device but it is just not working. The file is nothing more than a flat file on a unix box. Here is just a... (3 Replies)
Hello,
So I sorted my file as I was supposed to:
sort -n -r -k 2 -k 1 file1 | uniq > file2
and when I wrote
> cat file2
in the command line, I got what I was expecting, but in the script itself
...
sort -n -r -k 2 -k 1 averages | uniq > temp
cat file2
It wrote a whole... (21 Replies)
I am not sure if using cat -n is the most efficient way to split a file into multiple files, one file per line in the source file.
I thought using cat -n would make it easy to process the file because it produces an output that numbers each line that I could then grep for with the regex "^ *$i".... (3 Replies)
Hi,
I am looking for the following:
1. A command to 'grep' the variable from a file
2. And check whether the entered variable is empty in that file
I have a file as given below:
IAGLOBAL_USERID=admin
I want to check with a whether the variable contains a value, say here its admin if... (2 Replies)
Hi.
I'm just wondering how can I read variable text files through cat command.
I made a shell script to count frequency of words and array them with variable conditions. It's only working for one file that I wrote in script now. But I want to make it working for every text file when I execute... (2 Replies)
Hello
someone told me to use
OS=`awk '{print int($3)}' < /etc/redhat-release`
instead of
OS=cat /etc/redhat-release | `awk '{print int($3)}'`
any idea for the reason ? (5 Replies)
Hi ,
I am executing 2 queries and output is saved in file1.txt and file2.txt
example of file1.txt
Testing word Doc.docx,/Lab/Development and Validation/Multitest/MT_010708/Testing,Development and Validation,root,11-Mar-2014,,,,,
Testing Excel _.xlsx,/Lab/Development and... (3 Replies)
Hi,
I'm writing a shell script and trying to grep a variable value, it works fine as long as there is a value in /tmp/list.out which is captured in $DSK but sometimes the file tends to be empty and that is where I'm having an issue while using grep which returns nothing. I know I can use something... (15 Replies)
Discussion started by: mbak
15 Replies
LEARN ABOUT DEBIAN
poe::filter::line
POE::Filter::Line(3pm) User Contributed Perl Documentation POE::Filter::Line(3pm)NAME
POE::Filter::Line - serialize and parse terminated records (lines)
SYNOPSIS
#!perl
use POE qw(Wheel::FollowTail Filter::Line);
POE::Session->create(
inline_states => {
_start => sub {
$_[HEAP]{tailor} = POE::Wheel::FollowTail->new(
Filename => "/var/log/system.log",
InputEvent => "got_log_line",
Filter => POE::Filter::Line->new(),
);
},
got_log_line => sub {
print "Log: $_[ARG0]
";
}
}
);
POE::Kernel->run();
exit;
DESCRIPTION
POE::Filter::Line parses stream data into terminated records. The default parser interprets newlines as the record terminator, and the
default serializer appends network newlines (CR/LF, or "x0Dx0A") to outbound records.
Record terminators are removed from the data POE::Filter::Line returns.
POE::Filter::Line supports a number of other ways to parse lines. Constructor parameters may specify literal newlines, regular
expressions, or that the filter should detect newlines on its own.
PUBLIC FILTER METHODS
POE::Filter::Line's new() method has some interesting parameters.
new
new() accepts a list of named parameters.
In all cases, the data interpreted as the record terminator is stripped from the data POE::Filter::Line returns.
"InputLiteral" may be used to parse records that are terminated by some literal string. For example, POE::Filter::Line may be used to
parse and emit C-style lines, which are terminated with an ASCII NUL:
my $c_line_filter = POE::Filter::Line->new(
InputLiteral => chr(0),
OutputLiteral => chr(0),
);
"OutputLiteral" allows a filter to put() records with a different record terminator than it parses. This can be useful in applications
that must translate record terminators.
"Literal" is a shorthand for the common case where the input and output literals are identical. The previous example may be written as:
my $c_line_filter = POE::Filter::Line->new(
Literal => chr(0),
);
An application can also allow POE::Filter::Line to figure out which newline to use. This is done by specifying "InputLiteral" to be undef:
my $whichever_line_filter = POE::Filter::Line->new(
InputLiteral => undef,
OutputLiteral => "
",
);
"InputRegexp" may be used in place of "InputLiteral" to recognize line terminators based on a regular expression. In this example, input
is terminated by two or more consecutive newlines. On output, the paragraph separator is "---" on a line by itself.
my $paragraph_filter = POE::Filter::Line->new(
InputRegexp => "([x0Dx0A]{2,})",
OutputLiteral => "
---
",
);
PUBLIC FILTER METHODS
POE::Filter::Line has no additional public methods.
SEE ALSO
Please see POE::Filter for documentation regarding the base interface.
The SEE ALSO section in POE contains a table of contents covering the entire POE distribution.
BUGS
The default input newline parser is a regexp that has an unfortunate race condition. First the regular expression:
/(x0Dx0A?|x0Ax0D?)/
While it quickly recognizes most forms of newline, it can sometimes detect an extra blank line. This happens when a two-byte newline
character is broken between two reads. Consider this situation:
some stream dataCR
LFother stream data
The regular expression will see the first CR without its corresponding LF. The filter will properly return "some stream data" as a line.
When the next packet arrives, the leading "LF" will be treated as the terminator for a 0-byte line. The filter will faithfully return this
empty line.
It is advised to specify literal newlines or use the autodetect feature in applications where blank lines are significant.
AUTHORS & COPYRIGHTS
Please see POE for more information about authors and contributors.
perl v5.14.2 2012-05-15 POE::Filter::Line(3pm)