if "$1" has some data in it - assume it is not unset - then var="$1" places data in to the variable "var". Okay?
You seem to want to be able to echo to the screen, not use echo to write to a variable from a child process - which is what I first gave you as a workaround.
This writes to the console.
Is this what you want?
how can i redirect standard input? i dont remember :/, though could you redirec not from a command? i mean, to redirect always stdin and stout (1 Reply)
I tried copy the output files from find command into a directory.
Example,
find / -name core 2>/dev/null | xargs cp????
I have known that we can use xargs to execute command lines from standard input but how to use it in this case.
Or I can do something besides xargs. (2 Replies)
Dear...
I have a scrpit that contains multiple read command.... when I run the script I have to enter 3 variables so that I can get the output..
but, I dont want to put those 3 inputs manually every time... I want to make a shell that reads the 3 inputs from a file.
the script name is... (4 Replies)
Hi All,
How do I provide the output of a command to another command which is waiting for an input from the user ?
Ex : I need to login to a device via telnet. In the script, initially I use the "read" command to get the IP Address, Username and Password of the device from the user. Now,... (1 Reply)
Hello,
I'm writting a korn script that executes a daemon in a remote server. The problem is that daemon doesn't go background until it receives an enter from the standard input, and it maintains the rsh opened until it get it. I'm looking for the best (efficient and elegant) way to do send the... (3 Replies)
Hello,
I am new to scripting.
How do I read multiple lines from the command line?
I know read reads one line, but if I have to read multiple lines, how should I do?
Thanks,
Prasanna (4 Replies)
So, I am new to shell scripting and have a few problems.
I know how to read from standard input but I do not know how to really compare it to say, a character. I am trying to compare it to a character and anything exceeding just a character, the user will get an output message, but the program... (7 Replies)
I have a program that requires the user to enter input values while it is being run
for example in bash
...
...
..
echo "Enter your input"
read input
echo $input
...
...
...I need to schedule this program with crontab, hence a problem, cronjobs run in the background, any ideas on how to... (10 Replies)
Just started learning Unix and received my first assignment recently. We haven't learned many commands and honestly, I'm stumped. I'd like to receive assistance/guidance/hints.
1. The problem statement, all variables and given/known data:
How do I write a shell script that takes in a file or... (4 Replies)
Discussion started by: fozilla
4 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)