Hi,
i want to read a text file whose content(single line) will be a number like 1 or 2 or 3 ..... what i want to do is to read the file and increment the content of the file, using unix scripting.
Regards,
Senthil Kumar Siddhan. (2 Replies)
hello everybody!
I want to create a file with permissions for read, write, and execute to everybody using C, so I write this code:
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
int main(){
int fileDescriptor;
fileDescriptor =... (2 Replies)
Hi,
i'd like to implmeent emergency shutdown script in case our AC dies and the temperature rises too high.
I can get core temperatures with:
sensors | grep Core | cut -c15-16
Result is:
23
18
18
13
21
18
15
17
How can I check if any of the cores is above eg. 80 (that's C of... (2 Replies)
hello guys i m new to shell scripting and can't find out why this structure is not right
I m guessing this happens because $LINESUM is a string . so how can i do this ?
i want my script to do so many loops as the number of the lines of one custom file.
#!/bin/bash
echo give me path name... (5 Replies)
Hi,
from the manual
listen(2): listen for connections on socket - Linux man page
It has a parameter called backlog and it limits the maximum length of queue of pending list.
If I set backlog to 128, is it means no more than 128 packets can be handled by server?
If I have three... (3 Replies)
hi
I want to write a function which takes int as input and returns a string like this.
char GetString(int iNo)
{
switch(iNo)
{
case 0:
return "Zero";
break;
case 1:
return "One";
break;
}
}
void main()
{
int i;
printf("Enter... (1 Reply)
Hi,
I have the following requirement.
There will be following text/line in a file (eg: search-build.txt)
PRODUCT_VERSION="V:01.002.007.Build1234"
I need to update the incremental build number (eg here 007) every time I give a build through script. I am able to search the string and get... (4 Replies)
Hi,
I have column 5 in a file which contains string like this for ex.
RP11-125O5.2
SLCO1B1
CAPN1
FRMPD2
TXNL4B
So I do by
data = )]
ValueError: invalid literal for int() with base 10: 'R'
Can someday tell me how to convert this column into int successfully.
Thank You in... (7 Replies)
Discussion started by: rossi
7 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)