Variables don't work that way. Dynamic variable names are discouraged in general -- that's the sort of thing you should be using an array or even just a space-separated string for.
You can dereference a variable name with ${!...} however. (This is a BASH-only feature.)
You must assign the complete variable name to a string first, you can't put substitutions directly inside the ${}.
Struggling to add numbers in shell script..
ie.
a=3
b=4
c=$a + $b
echo $c
I thought this should give me 7 - but cannot see what wrong.. should be simple answer eh? (8 Replies)
Hello all,
Can somebody explain to me how set up a basename and dirname variable to simplify this script. I currently have a 'infile' with the contents of FTTPDataPVC_ & BaaisDSLFeed. I need to add a basename and or dirname variable so that any additions can be made through the infile and not... (1 Reply)
Hi All,
I need to pass a variable to perl script from bash script, where in perl i am using if condition. Here is the cmd what i am using in perl
FROM_DATE="06/05/2008"
TO_DATE="07/05/2008"
"perl -ne ' print if ( $_ >="$FROM_DATE" && $_ <= "$TO_DATE" ) ' filename"
filename has... (10 Replies)
hi,
i have a script that runs on bash and would like to run it on a machine that has csh and bash. the default setting on that machine is csh. i dont want to change my code to run it with a csh shell. is there any way i can run the script (written in bash) on this machine? in other words is there... (3 Replies)
# check host value regex='^(||1|2|25)(\.(||1|2|25)){3}$' if ')" != "" ]; then if ]; then echo host $host not found exit 4 fi elif ]; then echo $host is an invalid host address exit 5 fi
espeacailly the top regex part?
---------- Post updated at 06:58 PM ---------- Previous update was... (1 Reply)
So I'm trying to pass certain json elements as env vars and use them later on in a script.
Sample json:
JSON='{
"Element1": "file-123456",
"Element2": "Name, of, company written in, a very weird way",
"Element3": "path/to/some/file.txt",
}'
(part of the) script:
for s... (5 Replies)
I'm new to utilities like socat and netcat and I'm not clear if they will do what I need.
I have a "compileDeployStartWebServer.sh" script and a "StartBrowser.sh" script that are started by emacs/elisp at the same time in two different processes.
I'm using Cygwin bash on Windows 10.
My... (3 Replies)
Im looking for 2 Files -> *.WAV and *.wav with
find . -name 'unavail.wav' -o -name 'unavail.WAV' I need to list the Folders that contains these 2 Files?
Thx in advance (13 Replies)
In Bash shell - the ps -ef shows only the /bin/bash but the script name is not displayed ? Is there any way to get the script names for the process command ?
--- Post updated at 08:39 AM ---
in KSH (Korn Shell), my command output shows the script names but when run in the Bash Shell... (3 Replies)
So, let's say I have a usual batch rename file like this:
and I'd like to have a secon bat file, that can /reverse" the first.
BUT, I don't want to simply "rewrite" it like
move hello 254352426
but rather, have the new script take the source and destination and reverse it somehow... (6 Replies)
Discussion started by: pasc
6 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)