Hi,
I am new to unix. Is their a way to pass the output of the line below to a variable var1.
ls -1t | head -1.
I am trying something like var1=ls -1t | head -1, but I get error.
Situation is: I get file everyday through FTP in my unix box. I have to write a script that picks up first... (1 Reply)
I have a shell script which does the encryption of a file where i am passing the file name as a command line argument,but later on the script waits on the screen to enter Y or N
what is the command i should be using on the shell script
#!/bin/bash -x
outfilename=file.out
echo... (8 Replies)
Hi,
I have a very small requirement where i need to pass command output as an argument while invoking the shell script..
I need to call like this
sh testscript.sh ' ls -t Appl*and*abc* | head -n 1'
This will list one file name as ana argument..
I will be using "$1" in the shell... (2 Replies)
i want to write a shell script function that will ftp the files passed in the command line . i have written a shell script for ftp but how will it do for all files passed in command line argument ,
i am passing 4 files as argument
./ftp.sh file1 file2 file3 file4
code written by me... (5 Replies)
I have one working awk command line. Which taking data from the “J1202523.TXT” file and generating the “brazil.dat” file. PFB code.
awk '{ DUNS = substr($0,0,9);if ( substr($0,14,3) == "089" ) print DUNS }' J1202523.TXT > Brazil.dat
But now I want to pass two parameter as a command line argument... (4 Replies)
Hello all,
New to C and I'm trying to write a program which can run a unix command. Would like to have the option of giving the user the ability to enter arguments e.g for "ls" be able to run "ls -l".
I would appreciate any help.
Thanks
#include <stdio.h>
#include <unistd.h>
#include... (3 Replies)
Hi,
I have a requirement to work on script, it should take either of arguments.
wrote it as below.
#!/bin/bash
usage() {
echo "$0: missing argument OR invalid option !
Usage : $0 -m|-r|-d
}
while getopts mrdvh opt; do
case "$opt" in
m) monitor_flag=monitor;;... (1 Reply)
I need to write a shell script, when I run that script I should pass those arguments if not, then script should not run and pass the error message like
invalid option - - should pass the argument.
and Exit from the script
https://www.unix.com/images/misc/progress.gif (1 Reply)
I need to write a shell script, when I run that script I should pass those arguments if not, then script should not run and pass the error message like
invalid option - - should pass the argument.
and Exit from the script (8 Replies)
Discussion started by: Nsharma3006
8 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)