jotne posted an interesting thread an hour or two ago, and ended up with the following:
I had a question about the effect of $1=$1 assignment, and thought it better to start a new thread, because it's really a different topic.
Each one makes perfect sense to me, except for the last one. Could someone explain why $1=$1 results in blanks being removed from $0 var? What is going on behind the scene?
I'm sure this has been discussed before, but I could not find it on searching the forum archives. It disallowed the word "itself".
I run the following command in some of my folders... and ended up with a huge mess!!
find . -type f -exec perl -e 's/blabla/zzzxxxx/gi' -p -i.bak {} \;
I had to kill the process and later when I checked with one of my folders..
ls
vaditerm.dt.bak
vaditerm.dt.bak.bak... (2 Replies)
hi there,
i am porting kernel 2.2 driver program to kernel 2.6. for some extent i am successfull but some times the system gets hanged. what might be the problem? i am not able to get any help from log messages as nothing is being printed at that moment. hey does this kernel preemptiveness and... (2 Replies)
Hi,
I have noticed that rm -if will perform completely different to rm -fi. Whats the pattern of how I put my options to the script in relation to how it will act.
i.e
rm -fi treat the remove as interative but
rm -if treats it as forced
Thansk, Chris. (1 Reply)
2008-10-31T22:46:14+01:00
http://geekandpoke.typepad.com/.a/6a00d8341d3df553ef010535ce543e970c-800wi
Nicholas Carr (and here) has some problems with Tim O'Reilly's theory about the cloud and the network effect.
http://feeds.feedburner.com/~f/GeekAndPoke?i=OFn0M... (0 Replies)
Hello,
In google: if we type the text like :-
It gives us a question saying :-
I want to know how to write a shell script to give this Dictionary effect. example:If we give "lst" then it corrects us saying "list".
Can you please help me with a sample code! friends..... (3 Replies)
A basic cron question and I hope I explain it enough.
If a person creates a file to use with cron and issues the followin command:
crontab
I understand this will set the cron entries to whatever is in . However, if we now edit the crontab with:
crontab -e
and save, how does cron... (3 Replies)
Hi,
I have a situation to compare one file, say file1.txt with a set of files in directory.The directory contains more than 100 files.
To be more precise, the requirement is to compare the first field of file1.txt with the first field in all the files in the directory.The files in the... (10 Replies)
It doesn't have effect in script but it works on the terminal
root@server:/opt/kvm/usecases/logs# alias echo='echo -e'
root@server:/opt/kvm/usecases/logs# echo "xxxx\n"
xxxx
root@server:/opt/kvm/usecases/logs# cat xx.sh
#!/bin/bash
alias echo='echo -n'
echo "sssf \n"
... (3 Replies)
Dear all,
I have a data test.txt as below.
X22.30799720_T cg03868770 -0.5645412582127 2.4084685750406e-175
X22.30781182_A cg03868770 -0.5620426397492 3.5818034129169e-172
X22.30780724_C cg03868770 -0.5616890165605 2.9765569717858e-168
what I want is:
X22.30799720_T cg03868770... (3 Replies)
Discussion started by: forevertl
3 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)