Ok, but do you understand how the given code works? I should read some books or Google for some tutorials.
Anyway, to answer your question, some things to unravel:
I have a question. Take the following statement
awk -F\| '{print $21}' testfile | sed 's/\//\\/g' > newfile
This will grab the 21st column of a | delimited text file, replace the forward slashes "/" , with back slashes "\", and redirect the output newfile. Now, how do I get the output... (4 Replies)
Hello,
I am new to shell scripting. I want to optimize my one of the script.
I have one file and i want to remove selected zones for domains from that file.In this file i have almost 3500 zones for domains.Sample data for the file....
named.backup... (0 Replies)
Hi.
I'm going to learn scripting and i have the following topics on the list: sed, awk, shell scripting, perl.
My question is, whehter i should learn sed and awk? Aren't this tools outdated?
Although i see that GNU upgrade it's versions of these tools from time to time.
And, the next... (9 Replies)
Hello,
Despite reading the Pattern Matching chapter in the O'Reilly Sed & Awk book several times and
looking at numerous examples, I cannot seem to get any kind of conditional script to work in my awk scripts!
I am able to do the basic awk and grep script to capture the data but when I do with... (0 Replies)
I have large number of data files, close to 300 files, lets say all files are same kind and have extension .dat , each file have mulitple lines in it.
There is a unique line in each file containing string 'SERVER'. Right after this line there is another line which contain a string 'DIGIT=0',... (4 Replies)
Hi Experts,
I am studying SED and AWK text processing commands with an E-book. I am not satisfied with the way of explanation and examples given by them.
I would like you guys to suggest me the Best book for SED and AWK to become good in this utility.
Thanks in Advance (1 Reply)
string="din&esh\nisgood"
File.txt:
the name is
sed "s#\#${string}#g" File.txt
Output am getting:
the name is dinesh
is good
Expected output:
the name is din&esh\nisgood
The input string is dynamic it will be keep on changing
am able to handle & by placing \& in the string.. (5 Replies)
Discussion started by: dineshaila
5 Replies
LEARN ABOUT PHP
eval
EVAL(3) 1 EVAL(3)eval - Evaluate a string as PHP codeSYNOPSIS
mixed eval (string $code)
DESCRIPTION
Evaluates the given $code as PHP.
Caution
The eval(3) language construct is very dangerous because it allows execution of arbitrary PHP code. Its use thus is discouraged.
If you have carefully verified that there is no other option than to use this construct, pay special attention not to pass any user
provided data into it without properly validating it beforehand.
PARAMETERS
o $code
- Valid PHP code to be evaluated. The code mustn't be wrapped in opening and closing PHP tags, i.e. 'echo "Hi!";' must be passed
instead of '<? echo "Hi!"; >'. It is still possible to leave and reenter PHP mode though using the appropriate PHP tags, e.g.
'echo "In PHP mode!"; ?>In HTML mode!<? echo "Back in PHP mode!";'. Apart from that the passed code must be valid PHP. This
includes that all statements must be properly terminated using a semicolon. 'echo "Hi!"' for example will cause a parse error,
whereas 'echo "Hi!";' will work. A return statement will immediately terminate the evaluation of the code. The code will be exe-
cuted in the scope of the code calling eval(3). Thus any variables defined or changed in the eval(3) call will remain visible
after it terminates.
RETURN VALUES eval(3) returns NULL unless return is called in the evaluated code, in which case the value passed to return is returned. If there is a
parse error in the evaluated code, eval(3) returns FALSE and execution of the following code continues normally. It is not possible to
catch a parse error in eval(3) using set_error_handler(3).
EXAMPLES
Example #1
eval(3) example - simple text merge
<?php
$string = 'cup';
$name = 'coffee';
$str = 'This is a $string with my $name in it.';
echo $str. "
";
eval("$str = "$str";");
echo $str. "
";
?>
The above example will output:
This is a $string with my $name in it.
This is a cup with my coffee in it.
NOTES
Note
Because this is a language construct and not a function, it cannot be called using variable functions.
Tip
As with anything that outputs its result directly to the browser, the output-control functions can be used to capture the output of
this function, and save it in a string (for example).
Note
In case of a fatal error in the evaluated code, the whole script exits.
SEE ALSO call_user_func(3).
PHP Documentation Group EVAL(3)