Hello!
Is it anyone who might know how to extract the n last lines from a file, typically the 1000 last? Until know I have used sed -n np filename, but it takes each line separately, and is hence very time consuming.
Thank you in advance! (3 Replies)
Match column 3 in file1 to column 1 in file 2 and replace with column 2 from file2
file 1 sample
SNDK 80004C101 AT
XLNX 983919101 BB
NETL 64118B100 BS
AMD 007903107 CC
KLAC 482480100 DC
TER 880770102 KATS
ATHR 04743P108 KATS... (7 Replies)
Can anyone please help with this? I have 2 files as given below.
If 2nd column of file1 has pattern foo1@a, find the matching 1st column in file2 & replace 2nd column of file1 with file2's value.
file1
abc_1 foo1@a ....
abc_1 soo2@a ...
def_2 soo2@a ....
def_2 foo1@a ........ (7 Replies)
Hi Bigshots,
I have a pattern file with two columns. I have another data file. If column 1 in the pattern file appears as the 4th column in the data file, I need to replace it (4th column of data file) with column 2 of the pattern file. If the pattern is found in any other column, it should not... (6 Replies)
Hi,
I want to replace the value in more than one column.
For one column ,following command is working -
sed 's/./$value_to_replace/$column number' file_name
e.g. suppose this is input 1111000000
command - sed 's/./M/5'
output= 1111M000000
For two column also command is like -
cat... (22 Replies)
hi i have sample data
a,b,c,d,e,g h http://mysite.xyx
z,b,d,f,e,s t http://123124#
a,b,c,i,m,nothing
d,i,j,e,w,nothing
output expected is
a,b,c,d,e,http://mysite.xyx
z,b,d,f,e,http://123124#
a,b,c,i,m,nothing
d,i,j,e,w,nothing
i can get only links using grep -o 'http.*'
i... (8 Replies)
Hi Experts,
Please bear with me, i need help
I am learning AWk and stuck up in one issue.
First point : I want to sum up column value for column 7, 9, 11,13 and column15 if rows in column 5 are duplicates.No action to be taken for rows where value in column 5 is unique.
Second point : For... (12 Replies)
I have a csv which has lot of columns . I was looking for an awk script which would extract a column twice. for the first occurance the header and data needs to be intact but for the second occurance i want to replace the header name since it a duplicate and extract year value which is in ddmmyy... (10 Replies)
file1:
Name,Threshold,Curr Samples,Curr Error%,Curr ART
GETHome,100,21601,0.00%,47
GETregistry,100,21592,0.00%,13
GEThomeLayout,100,30466,0.00%,17
file2:
Name,Threshold,Curr Samples,Curr Error%,Curr ART
GETHome,100,21601,0.00%,33
GETregistry,100,21592,0.00%,22... (6 Replies)
Discussion started by: Raghuram717
6 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)