Okay, this probably sounds dumb for anyone who knows the answer, but I'm completely lost. I have to use the head command to search a directory AND all of its subdirectories to display the first line of all .txt files. I know how to do this: head -1 ~/UnixCourse/*.txt, but that does not search the... (4 Replies)
I am trying to do a head on a mainframe file and on doing ti just gives me a blank screen with nothing on it.
however, when i do a tail for the same file...i get a few lines on the screen.
i know tht mainframe files have all the records on one line...does this have to do something with this.... (10 Replies)
Im running the below commands in a script.
Total_confirms=`cat $OUTPATH/count_po* | head -4 | tail -1`
#
echo "Total Confirms records we need: $Total_confirms" >> $LOG2
The problem is its always returning 4 spaces before the result.. Can I pipe the result into something else to remove the... (5 Replies)
Hi friends,I am new to unix and this is really a dummy question.but please help me out.
How to simulate head command without using head command???
also tail command too,also more command.
it is given as a homework to do....please tell me how to do (2 Replies)
Hi, I have the following problem. I have files with one column of data (let's say file1.dat, file2.dat...file6.dat), and I would like to record the first value of the column of each file into another file (let's name it fileall.dat), which would have the the six values, one in each column. I use to... (4 Replies)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
I've been stuck on this problem for 2 days now
What command would you enter to list the first lines of all text... (11 Replies)
Hi,
I need some advise on whether there is a better way of doing what I am currently planning to do. Perhaps I should be using arrays instead of re-directing output to files?
I need to use a tool/program named ADRCI provided by Oracle to remove trace files that it generates. Honestly it is... (1 Reply)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
Write a script that allows the user to print the first n lines or the last n lines of every file in the... (18 Replies)
we have a file as below
AREA,COUNTRY,RANK
A,MX,1
A,MX,2
A,MX,5
A,MX,8
A,IN,7
A,IN,5
A,IN,21
B,CN,6
B,CN,2
B,CN,8
B,CN,0
we need the TOP 2 RANK records for the combination of Area, Country as below. i know head -2, which gives top 2 records from file but not sure it lists based on... (7 Replies)
Discussion started by: JSKOBS
7 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)