[BASH] eval command not expanding variables as expected.
Hi Guys,
I wrote a collection of bash functions years ago and now need to use them again but
I'm getting some error messages when eval tries to expand the variables names.
I recollect that I used the shopt command to set one of the options but I can't quite
remember the command that I used. However, I may be wrong regarding the shopt
command.
Anyway, the function in question is:
This is the output from the sh -x command:
The __SRC__ variable contains a relative reference to a file i.e. ~/djia.csv but I've also
tried using an absolute reference from the root directory which also does not get found.
I have a little script to help me manage a gallery of image files. It makes symbolic links to every file in and below the current directory, placing them in a target directory which is passed to the script as a parameter. Unfortunately, the script pukes when I pass a parameter that contains... (4 Replies)
If have
var='$variable'
how can I expand $variable.
I have tried many thing like duble quotes/braces etc, but nothing worked.
I need the solution ASAP. (2 Replies)
Hi,
The following code finds the line containing fruits in test.txt and replaces instances of apple with banana.
ed -s test.txt <<< $'/fruits/s/apple/banana/g\nw'
What I want to do is put variables in the place of fruits, apple and banana.
I have tried replacing ' with " to get... (2 Replies)
Hi,
I need some direction with the following. The below code is semi-psuedo code which will hopefully make it easier to understand what I am trying to achieve:
for i in `echo ${testarray
}`
do
let c=c+1
eval "first$c=$i"
while... (4 Replies)
Hello,
so i'm making a script, using dynamic variables and trying to expand them. So far it hasn't worked out too well so it seems that I need some help from you, the elite.
Example:
#!/bin/sh
counter=0
until (($counter>5))
counter2=1
until (($counter2>6)); do
if ;... (5 Replies)
Hi Guys,
I have an issue with awk and variables. I have trawled the internet and forums but can't seem to get the exactt syntax I need.
I have tried using awk -v and all sorts of variations but I have hit a brick wall. I have spent a full day on this and am just going round in circles.
... (3 Replies)
My OS is Linux (kernel 4.08.something) and AIX (7100-04-01-1543), the used ksh versions are:
ksh88: Version M-11/16/88f (AIX)
ksh93: Version M 93t+ 2009-05-01 (AIX), Version M 93u (Linux)
When writing a parser for stanza files in ksh i encountered a rather strange behavior. Here is a... (4 Replies)
I pass an argument to bash as run. The first command in green executes as expected, however the second in blue fails as the $run does not expand. I tried to escape the variable with \ thinking the quotes were making the literal translation and also "${run}" but both did not work to expand the... (3 Replies)
Discussion started by: cmccabe
3 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)