Hi All,
I am new to unix programming. I am trying for a requirement and the requirement goes like this.....
I have a test folder. Which tracks log files. After certain time, the log file is getting overwritten by another file (randomly as the time interval is not periodic). I need to preserve... (2 Replies)
Hi,
I have one .csv file. I have 2 date columns present in file, column 2 and column 3.
I need to calculate how many days exist between 2 dates.
I am trying to subtract date column 2 from date column 3.
Eg: my file look likes
s.no, Start_date,End_Date
1, 7/29/2012,10/27/2012
2,... (9 Replies)
Hi,
Can you please let me know code for the below (in korn shell)
a) Subtract month(s) from given date
b) Subtract day(s) from give date
c) Subtract month(s) from given timestamp
d) Subtract day(s) from give timestamp (1 Reply)
Hi Friends,
I have the following logfile. Currently time in india is 07/31/2014 12:33:34 and i have the following content in logfile. I want to display only those entries which contain string 'Exception' within last 3 hours. In this case, it would be the last line only
I can get the... (12 Replies)
Hello ,
I am working on AIX. I have to convert Unix timestamp to normal timestamp. Below is the file. The Unix timestamp will always be preceded by
EFFECTIVE_TIME as first field as shown and there could be multiple EFFECTIVE_TIME in the file : 3.txt
Contents of... (6 Replies)
So basically I have a log file and each line in this log file starts with a timestamp:
MON DD HH:MM:SS
SEP 15 07:30:01
I need to grep all the lines between last hour timestamp and current timestamp. Then these lines will be moved to a tmp file from which I will grep for particular strings. ... (1 Reply)
Hi all,
I have been researching to obtain SSL certification expiry for most of our webistes. For some cases, some hosts where not directly accessible so i finally got a solution working with curl using my proxy. This lists the expiry date which i'm finally looking for.
# curl --proxy... (4 Replies)
current date command runs well
awk -v t="$(date +%Y-%m-%d)" -F "'" '$1 < t' myname.dat
subtract 30 days fails
awk -v t="$(date --date="-30days" +%Y-%m-%d)" -F "'" '$1 < t' myname.dat
awk command in hp unix subtract 30 days automatically from current date without date illegal option error... (20 Replies)
Discussion started by: kmarcus
20 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)