Hi
following is a simple shell script,
--------------------------------
#!/usr/bin/tcsh
u=$USER
echo $u
string="cp c2960-lanbase-mz /tftpboot/$u/c2960-lanbase-mz"
string2="cp c2960-lanlite-mz /tftpboot/$u/c2960-lanlite-mz"
output=/users/$u/c2960-log.txt
if &&
then
echo... (1 Reply)
Hi all,
Im using a script which contains read command.. the script works perfectly but when I alias the script it gave "undifined variable" after I enter the read command input (variable)...
Does any one know why ? (4 Replies)
Hello,
#this script renames schematic file for model year change
#my = model year prefix
my="lsd"
for i in 'ls lsb*'
do
old=$i
new='echo $i | cut - c4 - c30'
mv $i $my$new
end
i: Undefined variable
What am I missing or doing wrong? (6 Replies)
Below script cuts date part from the date entered by the user.
#!/bin/csh
echo 'Enter date in the format dd/mm/yyyy'
read DATE
DD=`echo $DATE | cut -c1-2`
echo $DD;
when debug with -x option , it works perfectly but without -x doesnot.:confused:
$ sh -x unix_12.sh
+ echo Enter... (2 Replies)
Hello group,
Still fairly new at the whole scripting thing so be gentle. I'm trying to write a simple script that archives my log files into a master log broken into weeks of the year.
My script runs fine up till the "cat" lines which I get a undefined or illegal variable name error. But... (2 Replies)
hi there
I have this C shell script that was migrated from AIX to Linux, could someone please help me, I checked the syntax numerous times but I can't find out where the error is. The script is meant to find files older than 27 days and delete it
#!/usr/bin/csh
#
... (22 Replies)
Hi,
i am a beginner in ubuntu. my default shell is bash. everytime i try to change the shell with command "csh", i get a message (probably an error message). after i get into c-shell, when i try to execute a c shellscript, then it showed the same message. any idea about what is this about or any... (1 Reply)
i keep getting this error when i ssh using my id - any idea (2 Replies)
Discussion started by: tariq_m
2 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)