im trying to run the below if command
ifconfig -a |grep 10.100.120.21
gives me below output
inet addr:10.100.120.21 Bcast:10.100.120.255 Mask:255.255.255.0
i just want a basic shell which says if above exists then continue
how would i do this? (6 Replies)
Hi All,
I am new to shell scripting.
I have a variable which holds a numeric value.I have to check whether this variable holds a value between(0- 8),(8-17)(17-24).How do i write this syntax using if in shell scripting.
Thanks
Vignesh (2 Replies)
in shell scripting there is extensive usage of
i> regular expression
ii>sed
iii>awk
can anyone tell me the suitable contexts ...i mean which one is suitable for what kind of operation.
like the reg-exp and sed seems to be doing the same job..i.e pattern matching (1 Reply)
hi,
I am new script learner,
so my basic doubt is ,
how to store value of any command in a variable example
$ ls | wc -l
i want to stote the output of this in a variable c.
so that i can use c in if else loop.
and when do we use " ` " symbol in script..
can anyone also tell for... (5 Replies)
Lets say I wanted to create a script that would show what people are doing on my machine using the w command and refresh in about 6 seconds. What would be the easiest way to do this? I pretty much want the script to loop until I stop it.
I'm using the BASH shell by the way.
Help is appreciated.... (1 Reply)
Im trying to make a script that simply adds a word to the last available line in a txt file without overwriting any previous lines.
Ive googled this and there are great examples but no one explain what each function does, and i dont entirely understand how it works.
Basically Im looking for... (7 Replies)
Hey everyone, just now joined because I didn't want to go onto Ubuntu forums and start asking about how to write shell scripts. Seems like this is a pretty active forum for exactly what I need.
I'm trying to modify a shell script I found online, the end goal is to have it find all files in the... (9 Replies)
I need to have a script read a file that has a list of words in a single column like below:Black
Blue
Brown
Orange
Red
Yellow
Green
White
Purple
Silver
Grey
Tan
Then print to another file just all of the two-word possible combinations. Example:
Black,Blue
Anyone want to take a... (4 Replies)
Hello,
This is basic (i think). I am trying to run a shell script which would go into each folder (folder names defined in the list) and after entering would run some commands, once done, come out of the folder and continue until the list ends.
Pretty basic and there are bunch of example online. ... (9 Replies)
Discussion started by: Zam_1234
9 Replies
LEARN ABOUT PHP
debug_zval_dump
DEBUG_ZVAL_DUMP(3) 1 DEBUG_ZVAL_DUMP(3)debug_zval_dump - Dumps a string representation of an internal zend value to outputSYNOPSIS
void debug_zval_dump (mixed $variable, [mixed $...])
DESCRIPTION
Dumps a string representation of an internal zend value to output.
PARAMETERS
o $variable
- The variable being evaluated.
RETURN VALUES
No value is returned.
EXAMPLES
Example #1
debug_zval_dump(3) example
<?php
$var1 = 'Hello World';
$var2 = '';
$var2 =& $var1;
debug_zval_dump(&$var1);
?>
The above example will output:
&string(11) "Hello World" refcount(3)
Note
Beware the refcount
The refcount value returned by this function is non-obvious in certain circumstances. For example, a developer might expect the
above example to indicate a refcount of 2. The third reference is created when actually calling debug_zval_dump(3).
This behavior is further compounded when a variable is not passed to debug_zval_dump(3) by reference. To illustrate, consider a
slightly modified version of the above example:
Example #2
<?php
$var1 = 'Hello World';
$var2 = '';
$var2 =& $var1;
debug_zval_dump($var1); // not passed by reference, this time
?>
The above example will output:
string(11) "Hello World" refcount(1)
Why refcount(1)? Because a copy of $var1 is being made, when the function is called.
This function becomes even more confusing when a variable with a refcount of 1 is passed (by copy/value):
Example #3
<?php
$var1 = 'Hello World';
debug_zval_dump($var1);
?>
The above example will output:
string(11) "Hello World" refcount(2)
A refcount of 2, here, is extremely non-obvious. Especially considering the above examples. So what's happening?
When a variable has a single reference (as did $var1 before it was used as an argument to debug_zval_dump(3)), PHP's engine opti-
mizes the manner in which it is passed to a function. Internally, PHP treats $var1 like a reference (in that the refcount is
increased for the scope of this function), with the caveat that if the passed reference happens to be written to, a copy is made,
but only at the moment of writing. This is known as "copy on write."
So, if debug_zval_dump(3) happened to write to its sole parameter (and it doesn't), then a copy would be made. Until then, the
parameter remains a reference, causing the refcount to be incremented to 2 for the scope of the function call.
SEE ALSO var_dump(3), debug_backtrace(3), References Explained, References Explained (by Derick Rethans).
PHP Documentation Group DEBUG_ZVAL_DUMP(3)