Last updated on September 21st, 2023 at 08:01 am
In this tutorial I will walk you through the process step by step to
Read file line by line
This is the first thing we have to do. Let us assume that the file that contains data is oldfile.txt . In order to read this file we are using file() function and assigning the data to $lines as an array. At the same time we are counting the number of lines using count()
$filename='oldfile.txt';
$lines = file($filename);
$l_count = count($lines);
Now to read this file it is simple just use a for loop
for($x = 0; $x<$l_count; $x++)
{
echo $lines[$x];
}
This will print every line from from oldfile.txt
So if I simply execute that script you should see a similar output. I am also displaying the content of oldfile.txt before executing the script to read it.
root@production-server:~# cat oldfile.txt
this is good
that is bad
nice program
python and php
jvm and java
this is great
root@production-server:~# php ./run.php
this is good
that is bad
nice program
python and php
jvm and java
this is great
root@production-server:~#
Replace string in the file
Now we have read the file our next agenda is to find the word that we are looking for within the file. For that we can use str_replace()
$string_to_find="and"
$replace_with="*mistonline.in-Test*";
$newstring = str_replace($string_to_find, $replace_with, $lines[$x],$count);
In the above snippet we are defining $string_to_find = “and“. This means that the word we are looking for is and within the file.
As you can see inside the file we have two lines which contains word and ,
python and php
jvm and java
So the complete code to read the file line by line, search for the word and then replace the word and with *mistonline.in-Test* is shown below
$filename='oldfile.txt';
$string_to_find="and";
$replace_with="*mistonline.in-Test*";
$lines = file($filename);
$l_count = count($lines);
for($x = 0; $x<$l_count; $x++)
{
$newstring = str_replace($line, $replace_with, $lines[$x],$count);
if ($count > 0) {
$stringData = "$newstring";
echo "<br>\n".$stringData;
}
Update these 2 variables as per your requirement with any words of your choice
$string_to_find="and"
$replace_with="*mistonline.in-Test*"
In this example when I execute the code I was able to extract lines that contains the word and , replace it with *mistonline.in-Test* then print it in STDOUT
root@production-server:~# php replace.php
python *mistonline.in-Test* php
jvm *mistonline.in-Test* java
root@production-server:~#
Save replaced lines to a new file
This is the final step, complete code with word replacement along with saving those extracted lines to a new file is shown below
<?php
$filename='oldfile.txt';
$myFile = "newfile.txt";
$string_to_find="and";
$replace_with="*mistonline.in-Test*";
$lines = file($filename);
$l_count = count($lines);
for($x = 0; $x<$l_count; $x++)
{
$newstring = str_replace($string_to_find, $replace_with, $lines[$x],$count);
if ($count > 0) {
$fh = fopen($myFile, 'a') or die("can't open file");
$stringData = "$newstring";
echo "<br>\n".$stringData;
fwrite($fh, $stringData);
}
}
fclose($fh);
?>
As you might have noticed in the code we have defined $myFile = “newfile.txt” , this is the new file in which we save the replaced lines.
root@production-server:~# php ./run.php
python *mistonline.in-Test* php
jvm *mistonline.in-Test* java
root@production-server:~# cat newfile.txt
python *mistonline.in-Test* php
jvm *mistonline.in-Test* java
root@production-server:~#
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