Hi There,
I've written a script that processes a data file on our system. Basically the script reads a post code from a list file, looks in the data file for the first occurrence (using grep) and reads the line number. It then tails the data file, with the line number just read, and outputs to a... (3 Replies)
I'm trying to find a command which will allow me to remove a range of lines (2-4) from a .dat file from the command line without opening the file.
Someone mentioned using the ex command?
Does anyone have any ideas?
thanks (6 Replies)
Hi Gurus,
I'm a little new to UNIX. How can I do remove the first and last line in a file? Say, supppose I have a file as below:
Code:
1DMA
400002BARRIE
401002CALGARY/LETHBRI
402002CARLETON
500001PORTLAND-AUBRN
501001NEW YORK, NY
502001BINGHAMTON, NY ... (2 Replies)
Hi folks, I have a long string of DNA sequences, and I need to remove several lines, as well as the line directly following them. For example, here is a sample of my starting material:
>548::GY31UMJ02DLYEH rank=0007170 x=1363.5 y=471.0 length=478... (1 Reply)
Hi there, normally if I want to remove a user tht I have added to a specific group, i would do the following
this is what my group2 looks like
# grep group2 /etc/group
group2:x:7777:user2,user1,user4
user1 has been defined in a few groups
# id -nG user1
group1 group2 group3
So... (3 Replies)
I have a reference file that needs to remain static and another file that may or may not have duplicate rows that match the reference file. I need help with a command that will delete any duplicate rows from the second file while leaving reference file intact
For example reference file would... (4 Replies)
Hello Everyone,
I'm currently have a requirement where I've generated a list of files with specific attributes and I need to know what lines are similar between the two files. For example:
-File 1-
line1
line2
line3
-File 2-
line1
line2
line4
line5
-Desires Output-
line1
line2... (5 Replies)
Hi,
I have a linux server that was hacked and I have a bunch of files that sporadically contain the following lines through out the file:
<?php eval(base64_decode("Xxxxxxxxxxxxxx/xxxxxxxx"));
I did't put the exact lines of the file in this post. The "Xxxx" are random letters/numbers.... (8 Replies)
I have a file `/tmp/wrk` containing filenames with paths. I want to remove filenames
from this file, for example
remove all filenames containing alja cagr cavt clta cmdo or corl
remove all filenames containing data for days in region `d.2016.001` to `d.2016.207`
remove all filenames... (10 Replies)
Discussion started by: kristinu
10 Replies
LEARN ABOUT DEBIAN
devel::refcount
Devel::Refcount(3pm) User Contributed Perl Documentation Devel::Refcount(3pm)NAME
"Devel::Refcount" - obtain the REFCNT value of a referent
SYNOPSIS
use Devel::Refcount qw( refcount );
my $anon = [];
print "Anon ARRAY $anon has " . refcount($anon) . " reference
";
my $otherref = $anon;
print "Anon ARRAY $anon now has " . refcount($anon) . " references
";
DESCRIPTION
This module provides a single function which obtains the reference count of the object being pointed to by the passed reference value.
FUNCTIONS
$count = refcount($ref)
Returns the reference count of the object being pointed to by $ref.
COMPARISON WITH SvREFCNT
This function differs from "Devel::Peek::SvREFCNT" in that SvREFCNT() gives the reference count of the SV object itself that it is passed,
whereas refcount() gives the count of the object being pointed to. This allows it to give the count of any referent (i.e. ARRAY, HASH,
CODE, GLOB and Regexp types) as well.
Consider the following example program:
use Devel::Peek qw( SvREFCNT );
use Devel::Refcount qw( refcount );
sub printcount
{
my $name = shift;
printf "%30s has SvREFCNT=%d, refcount=%d
",
$name, SvREFCNT($_[0]), refcount($_[0]);
}
my $var = [];
printcount 'Initially, $var', $var;
my $othervar = $var;
printcount 'Before CODE ref, $var', $var;
printcount '$othervar', $othervar;
my $code = sub { undef $var };
printcount 'After CODE ref, $var', $var;
printcount '$othervar', $othervar;
This produces the output
Initially, $var has SvREFCNT=1, refcount=1
Before CODE ref, $var has SvREFCNT=1, refcount=2
$othervar has SvREFCNT=1, refcount=2
After CODE ref, $var has SvREFCNT=2, refcount=2
$othervar has SvREFCNT=1, refcount=2
Here, we see that SvREFCNT() counts the number of references to the SV object passed in as the scalar value - the $var or $othervar
respectively, whereas refcount() counts the number of reference values that point to the referent object - the anonymous ARRAY in this
case.
Before the CODE reference is constructed, both $var and $othervar have SvREFCNT() of 1, as they exist only in the current lexical pad. The
anonymous ARRAY has a refcount() of 2, because both $var and $othervar store a reference to it.
After the CODE reference is constructed, the $var variable now has an SvREFCNT() of 2, because it also appears in the lexical pad for the
new anonymous CODE block.
PURE-PERL FALLBACK
An XS implementation of this function is provided, and is used by default. If the XS library cannot be loaded, a fallback implementation in
pure perl using the "B" module is used instead. This will behave identically, but is much slower.
Rate pp xs
pp 225985/s -- -66%
xs 669570/s 196% --
SEE ALSO
o Test::Refcount - assert reference counts on objects
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.14.2 2011-11-15 Devel::Refcount(3pm)