Hello ,
I am trying to print the footer of evry file in the given directory with xargs command like follows
ls -1 | xargs -I {} gzcat {} | tail -1
now problem with this is only last file foooter is getting printed as " | tail -1 " is getting executed for the last file.
I know this can... (4 Replies)
I am trying to write a script that will ssh into a remote machine and recurse through a specified directory, find mp3 files which may be two or three directories deep (think iTunes: music/artist/album/song.mp3), and scp them back to the machine running the script. The script should also maintain... (3 Replies)
Hello,
I have multiple functions within a shell script. eg. function_database_backup, unix_tar_creation, etc.
I would like to run these functions in parallel, as each is independent of the other.
If these were simple commands, I could have probably run each of the commands in background.
... (1 Reply)
Hi,
I am using ksh , i have requirement to run 4 functions in background , 4 functions call are available in a case that case is also in function, i need to execute 1st function it should run in background and return to case and next i will call 2nd function it should run in background and... (8 Replies)
Hello. There is my one-liner to get subjects of potential spam mails
sudo exiqgrep -bf "spamer@example.com" |cut -d' ' -f1 |xargs -I ~ sudo /usr/sbin/exim -Mvh ~ |grep 'Subject: '
I want to insert blank line after each iteration to make output more readable. I tried
sudo exiqgrep -bf... (1 Reply)
I have a script (ksh) which tries to run a function in parallel for performance gains. I am also trying to limit the number of parallel child processes to avoid overloading the system by using a variable to count triggered processes and waiting for completion e.g.
do_something ()
{
...
}
... (9 Replies)
Hi,
I am a beginner in python programming. In my python script have a main function which calls several other functions. The main function gets its input by reading lines from a input text file. I call the main function for every line in input text file through a loop.
def main(line):
var1... (6 Replies)
Hello,
I have a requirement to apply hashing algorithm on flat file on one or more columns dynamically based on header
sample input file
ID|NAME|AGE|GENDER
10|ABC|30|M
20|DEF|20|F
say if i want multiple columns based on the header example id,name or id,age or name,gender and hash and... (13 Replies)
I am running the below loop that to process the 3 bam files (which isn't always the case). A .py executable is then called using | xargs sh to further process. If I just run it with echo the output is fine and expected, however when
| xargs sh is added I get the error. I tried adding | xargs... (4 Replies)
Discussion started by: cmccabe
4 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)