But then it might not be ksh portable![CODE]$ echo "(( 1 + 2 ))"
(( 1 + 2 ))
$ echo (( 1 + 2 ))
ksh: syntax error: `((' unexpected
That's not "unportable" -- that's simply wrong. BASH and KSH alike agree this is a syntax error, and for good reason:
Produces a string: $((stuff))
Produces no string: ((stuff))
Plain (( )) without the $ is more like a [ ] statement. Try it:
When you use them in a syntactically valid manner, as their own statement, they're fine: ((k = k + 5))
You also missed my point about k vs $k inside (( )). ((k=k+3)) works, (($k=$k+3)) does not since K gets substituted before anything starts calculating, so you end up trying to assign the value of 3 or something. Just plain variable names don't ever need a $ inside a (( )) expression anyway, why make them more complicated?
Last edited by Corona688; 04-12-2011 at 04:08 PM..
Hi,
i am new to UNIX. I have couple of basic questions.
1. Is the syntax for BASH shell programming same in the LINUX and SUN SOLARIS operating systems?
2. I have to work on BASH shell programming in SUN SOLARIS operating system. I am going through the documentation from the following... (4 Replies)
Can any1 please help me...
i'm really lost in using bash shell scripting...
and i got to hand this up on monday...
please anyone teach me how to do this assignment...
Please use basic things because i just learn the program only... thanks
... (1 Reply)
Hi,
Actually i have written one test.sh (shell program) in bash.
Here i have a variables $a which stored the value package1.
Now I want to write a regular expression inside the if command that "if $a variable contains letter p in the begining of the value package1 then it is coming true.... (5 Replies)
#! /bin/sh
abcd = "Hello world"
if
then
echo $abcd
fi
i got error message that
line3 : abcd: command not found
line5 : [0: command not found
line5 : [1: command not found
i have no idea why i got this message. Can some one help me ??? (6 Replies)
i am new to shell scripting and stuck at one place in my program.
i am reading data from one structured file and extracting some data from particular lines and then writing into the output file. In that reading input file line by line from while loop.
while read line
do
rectype=line... (7 Replies)
Hello All,
I am setting up a cron job, where i am calling a shell script to make few builds. I got struck at a point, need some expert inputs to proceed further.
The script is categorized in 5 parts and in the last part while building software it asks for few questions like:-
1. Build mode... (4 Replies)
I'm having trouble trying to create a BASH shell script.
I want the user to input a command "cat file_name.c" and then the shell script will delete all comments "/* */" from file_name.c else exit.
So far I have this:
#!/bin/bash
read "cat file" // User will input command cat... (7 Replies)
I do not know shell scripting. But at work place, I have got an in and out shell scripting task. I just need to understand a very big script. Is there any tool in which I can place the script and it can tell me the meaning of the whole script? (3 Replies)
Discussion started by: lg123
3 Replies
LEARN ABOUT PHP
echo
ECHO(3) 1 ECHO(3)echo - Output one or more stringsSYNOPSIS
void echo (string $arg1, [string $...])
DESCRIPTION
Outputs all parameters.
echo is not actually a function (it is a language construct), so you are not required to use parentheses with it. echo (unlike some other
language constructs) does not behave like a function, so it cannot always be used in the context of a function. Additionally, if you want
to pass more than one parameter to echo, the parameters must not be enclosed within parentheses.
echo also has a shortcut syntax, where you can immediately follow the opening tag with an equals sign. Prior to PHP 5.4.0, this short syn-
tax only works with the short_open_tag configuration setting enabled.
I have <?=$foo?> foo.
PARAMETERS
o $arg1
- The parameter to output.
o $...
-
RETURN VALUES
No value is returned.
EXAMPLES
Example #1
echo examples
<?php
echo "Hello World";
echo "This spans
multiple lines. The newlines will be
output as well";
echo "This spans
multiple lines. The newlines will be
output as well.";
echo "Escaping characters is done "Like this".";
// You can use variables inside of an echo statement
$foo = "foobar";
$bar = "barbaz";
echo "foo is $foo"; // foo is foobar
// You can also use arrays
$baz = array("value" => "foo");
echo "this is {$baz['value']} !"; // this is foo !
// Using single quotes will print the variable name, not the value
echo 'foo is $foo'; // foo is $foo
// If you are not using any other characters, you can just echo variables
echo $foo; // foobar
echo $foo,$bar; // foobarbarbaz
// Some people prefer passing multiple parameters to echo over concatenation.
echo 'This ', 'string ', 'was ', 'made ', 'with multiple parameters.', chr(10);
echo 'This ' . 'string ' . 'was ' . 'made ' . 'with concatenation.' . "
";
echo <<<END
This uses the "here document" syntax to output
multiple lines with $variable interpolation. Note
that the here document terminator must appear on a
line with just a semicolon. no extra whitespace!
END;
// Because echo does not behave like a function, the following code is invalid.
($some_var) ? echo 'true' : echo 'false';
// However, the following examples will work:
($some_var) ? print 'true' : print 'false'; // print is also a construct, but
// it behaves like a function, so
// it may be used in this context.
echo $some_var ? 'true': 'false'; // changing the statement around
?>
NOTES
Note
Because this is a language construct and not a function, it cannot be called using variable functions.
SEE ALSO print(3), printf(3), flush(3), Heredoc syntax.
PHP Documentation Group ECHO(3)