Please, do not advocate the use of eval unnecessarily because it is a security risk. It should be reserved with tightly controlled commands and in this case this is certainly not tight controlled.
Perl does allow you reference a "variable variable" (a variable whose name is the value held by a variable). That works unless you are in strict mode, in which case an exception will be thrown.
Even though that works, think about it carefully whether you really need that because not many use cases actually need this.
is it possible to use eval to create constants in perl? i cannot seem to get anything to work, and my searches are turning up little to nothing. an example of what i am trying to do is this:
2 arrays:
array 1: 'FOOD','NUMBER','OS'
array 2: 'pizza','two','unix'
loop through the arrays and... (5 Replies)
Hi using the below cmd i am identifying wheether last character in each line in thousands of files as semicolon or not.If last character is semicolon i am removing semicolon .If last character is not semicolon then i am appending next line to present line .
For example my input file consists of... (4 Replies)
Hi,
I have 3 arrays:
@arr1=("Furthermore, apigenin treatment increased the level of association of the RNA binding protein HuR with endogenous p53 mRNA","one of the mechanisms by which apigenin induces p53 protein expression is enhancement of translation through the RNA binding protein... (1 Reply)
Hi all,
some small script with eval turned me to crazy.
my OS is linux
Linux s10-1310 2.6.16.53-0.8.PTF.434477.3.TDC.0-smp #1 SMP Fri Aug 31 06:07:27 PDT 2007 x86_64 x86_64 x86_64 GNU/Linux
below script works well
#!/bin/bash
eval ssh remotehost date
eval ssh remotehost ls
below... (1 Reply)
Hi All,
I read the above written code (perl code) in another perl script and evaluates this code for each line of text file,but using exit statement in code make this not to work and i could not get the desired results. However if i use return it works fine. I just need to know why it doesn't... (1 Reply)
Hello All,
I am trying to use perl eval in a complex code and below given is a pseudo code of my logic.
Here $result evalutes to empty.
Please help.How should I retrieve of $t where $f just hold the name of varaible i.e t
$t=10;
$f='$t';
$result=eval "\$$f";
print "$result\n"; (3 Replies)
I have the following string :
Cat dog fox catepillar bear foxy
I need to replace "cat" and "fox" words from this sentence to word "animal"
I do the following:
$Str1="cat";
$Str2="fox";
$NewStr="animal";
open(F1, "<$inputFile") or die "Error: $!";
open(F2, ">$outputFile") or... (1 Reply)
Discussion started by: AIX_30
1 Replies
LEARN ABOUT MOJAVE
global
global(n) Tcl Built-In Commands global(n)
__________________________________________________________________________________________________________________________________________________NAME
global - Access global variables
SYNOPSIS
global varname ?varname ...?
_________________________________________________________________DESCRIPTION
This command has no effect unless executed in the context of a proc body. If the global command is executed in the context of a proc body,
it creates local variables linked to the corresponding global variables (though these linked variables, like those created by upvar, are
not included in the list returned by info locals).
If varname contains namespace qualifiers, the local variable's name is the unqualified name of the global variable, as determined by the
namespace tail command.
varname is always treated as the name of a variable, not an array element. An error is returned if the name looks like an array element,
such as a(b).
EXAMPLES
This procedure sets the namespace variable ::a::x
proc reset {} {
global a::x
set x 0
}
This procedure accumulates the strings passed to it in a global buffer, separated by newlines. It is useful for situations when you want
to build a message piece-by-piece (as if with puts) but send that full message in a single piece (e.g. over a connection opened with socket
or as part of a counted HTTP response).
proc accum {string} {
global accumulator
append accumulator $string
}
SEE ALSO
namespace(n), upvar(n), variable(n)
KEYWORDS
global, namespace, procedure, variable
Tcl global(n)