It's a string test. Put double quotes round the string wherever you mention it. Without the quotes it is a syntax error in most Shells.
Code:
echo "$nothing"
if [ -z "${nothing}" ]; then echo "nothing is a zero length string"; fi
if [ -n "${nothing}" ]; then echo "nothing is also a non-zero length string, apparently"; fi
Hi
In the shell scripted I'm trying to write!
I would like to test the last character in a string. The string is a path/directory and I want to see if the last character is a '/'.
The string (path/directory) is inputted by a user. If the '/' character isn't present then I want to be able to... (11 Replies)
Hi guys, I hope you can help me with my problem.
I have a text file that contains lines like this:
78 ANGELO -809.05
79 ANGELO2 -5,000.06
I need to find all occurences of amounts that are negative and replace them with x's
78 ANGELO xxxxxxx
79... (4 Replies)
Hello All,
Plz help me with:
I have a csv file with data separated by ',' and optionally enclosed by "". I want to check each of these values to see if they exceed the specified string length, and if they do I want to cut just that value to the max length allowed and keep the csv format as it... (9 Replies)
Hi
lets say i have a variable
output="string"
how can you find the length of the string contained in this variable? i guess "wc" cannot be used. its only for files. (8 Replies)
I've never tested file length with shell before and I'm having problems. What I'm doing is testing $filename and $filename.bak to see if there is a difference. so I use 'diff' for that and send it to an output file 'dif.txt'. Now I wanna see if the length of 'dif.txt' is zero or not. that's where... (1 Reply)
Hello, I'm new to shell scripting and need a little help please.
I'm working on a script that asks the user to input a name that can be 1 to 12 alphanumeric characters and can have dots(.) dashes(-) and spaces. I want to test that the answer is valid and if not make the user try again. I have no... (4 Replies)
Helo,
I have character array of sixe 128
char filename
now I have one problem that when I enter filename as nothing I got value
as " " ",`\0` " .
when I find this string length ( " ",`\0`) as 1(one).
actually I want to make this length as zero.
so what should I do (10 Replies)
HI
In my script, i am reading the input from the user and want to find the length of the string.
The input may contain leading spaces. Right now, when leading spaces are there, they are not counted.
Kindly help me
My script is like below. I am using the ksh.
#!/usr/bin/ksh
echo... (2 Replies)
Hello, Unix-Forums!
Is there a command that can check how long a user-entered string is?
Please don't give me a code, just the name of the command (playing around yourself is much more fun than just pasting code)
edit: I'm sorry, first hit of the forum search gave me the answer. (1 Reply)
Discussion started by: intelinside
1 Replies
LEARN ABOUT PHP
substr
SUBSTR(3) 1 SUBSTR(3)substr - Return part of a stringSYNOPSIS
string substr (string $string, int $start, [int $length])
DESCRIPTION
Returns the portion of $string specified by the $start and $length parameters.
PARAMETERS
o $string
- The input string. Must be one character or longer.
o $start
- If $start is non-negative, the returned string will start at the $start'th position in $string, counting from zero. For
instance, in the string ' abcdef', the character at position 0 is ' a', the character at position 2 is ' c', and so forth. If
$start is negative, the returned string will start at the $start'th character from the end of $string. If $string is less than or
equal to $start characters long, FALSE will be returned.
Example #1
Using a negative $start
<?php
$rest = substr("abcdef", -1); // returns "f"
$rest = substr("abcdef", -2); // returns "ef"
$rest = substr("abcdef", -3, 1); // returns "d"
?>
o $length
- If $length is given and is positive, the string returned will contain at most $length characters beginning from $start (depend-
ing on the length of $string). If $length is given and is negative, then that many characters will be omitted from the end of
$string (after the start position has been calculated when a $start is negative). If $start denotes the position of this trunca-
tion or beyond, false will be returned. If $length is given and is 0, FALSE or NULL, an empty string will be returned. If
$length is omitted, the substring starting from $start until the end of the string will be returned.
Example #2
Using a negative $length
<?php
$rest = substr("abcdef", 0, -1); // returns "abcde"
$rest = substr("abcdef", 2, -1); // returns "cde"
$rest = substr("abcdef", 4, -4); // returns false
$rest = substr("abcdef", -3, -1); // returns "de"
?>
RETURN VALUES
Returns the extracted part of $string; or FALSE on failure, or an empty string.
CHANGELOG
+--------------+---------------------------------------------------+
| Version | |
| | |
| | Description |
| | |
+--------------+---------------------------------------------------+
|5.2.2 - 5.2.6 | |
| | |
| | If the $start parameter indicates the position |
| | of a negative truncation or beyond, false is |
| | returned. Other versions get the string from |
| | start. |
| | |
+--------------+---------------------------------------------------+
EXAMPLES
Example #3
Basic substr(3) usage
<?php
echo substr('abcdef', 1); // bcdef
echo substr('abcdef', 1, 3); // bcd
echo substr('abcdef', 0, 4); // abcd
echo substr('abcdef', 0, 8); // abcdef
echo substr('abcdef', -1, 1); // f
// Accessing single characters in a string
// can also be achieved using "square brackets"
$string = 'abcdef';
echo $string[0]; // a
echo $string[3]; // d
echo $string[strlen($string)-1]; // f
?>
Example #4
substr(3) casting behaviour
<?php
class apple {
public function __toString() {
return "green";
}
}
echo "1) ".var_export(substr("pear", 0, 2), true).PHP_EOL;
echo "2) ".var_export(substr(54321, 0, 2), true).PHP_EOL;
echo "3) ".var_export(substr(new apple(), 0, 2), true).PHP_EOL;
echo "4) ".var_export(substr(true, 0, 1), true).PHP_EOL;
echo "5) ".var_export(substr(false, 0, 1), true).PHP_EOL;
echo "6) ".var_export(substr("", 0, 1), true).PHP_EOL;
echo "7) ".var_export(substr(1.2e3, 0, 4), true).PHP_EOL;
?>
The above example will output:
1) 'pe'
2) '54'
3) 'gr'
4) '1'
5) false
6) false
7) '1200'
ERRORS /EXCEPTIONS
Returns FALSE on error.
Example #5
<?php
var_dump(substr('a', 1)); // bool(false)
?>
SEE ALSO strrchr(3), substr_replace(3), preg_match(3), trim(3), mb_substr(3), wordwrap(3), String access and modification by character.
PHP Documentation Group SUBSTR(3)