Hi,
Command "chfn" can be used to change finger information.. can anybody tell me how to unset i mean reset the same finger information.
Thanks in advance,
Chanakya (3 Replies)
Hi All,
May be this is a very simple question...
$ b=8
$ readonly b
$ echo $b
8
$ b=90
-bash: b: readonly variable
$ unset b
-bash: unset: b: cannot unset: readonly variable
I m not able to change the readonly mode of variable b
Please help me out..
Thanks
Nidhi (2 Replies)
Hi,
I am writing a BASH script. My questions regard deleting elements of arrays.
I have an array:
michael-browns-powerbook-g4-15:~ msb65$ test_array=(1 2 3 4)
michael-browns-powerbook-g4-15:~ msb65$ echo ${test_array}
1 2 3 4
To delete the second element of test_array I type:... (3 Replies)
can I use unset to unset all the variables in a shell sciprt?
VAR1=1
VAR2=2
VAR3=3
unset
whether this unset will afftect any system variables?
Thanks, (3 Replies)
I'm wondering, is the number of variables will affect execution time of my bash script or maybe affect the cpu workload, cpu memory, etc ?
If I create so many variables, should I unset each one of that variables after I used them or after I think they are no longer needed?
and if my script... (2 Replies)
I have a script with a $PASSWORD variable. I unset it right after using it, just to minimize the chance it could be left around for a snooper. That worked just fine... until I used a password with a value of "P@ssw0rd" Now, unset (even with -f, even with the variable enquoted) tells me: unset:... (1 Reply)
I have tried to thoroughly search other threads before posting this question...
I have a shell script (bsh) that I'd like to "re-execute" if the user chooses to. Before the program is executed again the local variables (those set within the script) need to be unset. Is there a command that... (6 Replies)
Hi all,
Does anyone know how to change PROC_MEM_RES?
We have a DB server with quite a few oracle instances (RAC) and we are getting critical alerts for PROC_MEM_RES.
Anyone know how to increase the current setting or what we should do about it?
Thanks in advance.
john (2 Replies)
Hi,
Can someone tell what is the path for "unset", I tried "which" command but getting below error
# which unset
/usr/bin/which: no unset in (/usr/lib/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin/:/root/bin) (9 Replies)
Discussion started by: stew
9 Replies
LEARN ABOUT PHP
unset
UNSET(3) 1 UNSET(3)unset - Unset a given variableSYNOPSIS
void unset (mixed $var, [mixed $...])
DESCRIPTION unset(3) destroys the specified variables.
The behavior of unset(3) inside of a function can vary depending on what type of variable you are attempting to destroy.
If a globalized variable is unset(3) inside of a function, only the local variable is destroyed. The variable in the calling environment
will retain the same value as before unset(3) was called.
<?php
function destroy_foo()
{
global $foo;
unset($foo);
}
$foo = 'bar';
destroy_foo();
echo $foo;
?>
The above example will output:
bar
To unset(3) a global variable inside of a function, then use the $GLOBALS array to do so:
<?php
function foo()
{
unset($GLOBALS['bar']);
}
$bar = "something";
foo();
?>
If a variable that is PASSED BY REFERENCE is unset(3) inside of a function, only the local variable is destroyed. The variable in the
calling environment will retain the same value as before unset(3) was called.
<?php
function foo(&$bar)
{
unset($bar);
$bar = "blah";
}
$bar = 'something';
echo "$bar
";
foo($bar);
echo "$bar
";
?>
The above example will output:
something
something
If a static variable is unset(3) inside of a function, unset(3) destroys the variable only in the context of the rest of a function. Fol-
lowing calls will restore the previous value of a variable.
<?php
function foo()
{
static $bar;
$bar++;
echo "Before unset: $bar, ";
unset($bar);
$bar = 23;
echo "after unset: $bar
";
}
foo();
foo();
foo();
?>
The above example will output:
Before unset: 1, after unset: 23
Before unset: 2, after unset: 23
Before unset: 3, after unset: 23
PARAMETERS
o $var
- The variable to be unset.
o $...
- Another variable ...
RETURN VALUES
No value is returned.
EXAMPLES
Example #1
unset(3) example
<?php
// destroy a single variable
unset($foo);
// destroy a single element of an array
unset($bar['quux']);
// destroy more than one variable
unset($foo1, $foo2, $foo3);
?>
Example #2
Using (unset) casting
(unset) casting is often confused with the unset(3) function. (unset) casting serves only as a NULL-type cast, for completeness. It
does not alter the variable it's casting.
<?php
$name = 'Felipe';
var_dump((unset) $name);
var_dump($name);
?>
The above example will output:
NULL
string(6) "Felipe"
NOTES
Note
Because this is a language construct and not a function, it cannot be called using variable functions.
Note
It is possible to unset even object properties visible in current context.
Note
It is not possible to unset $this inside an object method since PHP 5.
Note
When using unset(3) on inaccessible object properties, the __unset() overloading method will be called, if declared.
SEE ALSO isset(3), empty(3), __unset(), array_splice(3).
PHP Documentation Group UNSET(3)