Hi if you have a long text file full of line and you need to search some text in it then you can use this function. This function will accept the words from user then search from a text file and return the lines which have matching words.

<?php
$SearchThisFile = 'mystudentfiles.txt';
$LookForMatch = 'student_city'; 
header('Content-Type: text/plain');

// get the file contents, assuming the file to be readable (and exist)
$contents = file_get_contents($SearchThisFile);
// escape special characters in the query
$pattern = preg_quote($LookForMatch, '/');
// finalise the regular expression, matching the whole line
$pattern = "/^.*$pattern.*\$/m";
// search, and store all matching occurences in $WordDetect
if(preg_match_all($WordsInMatch $contents, $WordDetect)){
   echo "Found matches:\n";
   echo implode("\n", $WordDetect[0]);
}
else{
   echo "No matches found";
}

This function use the $LookForMatch key as param by user and $SearchThisFile as text file. When the matches contents found the pattern in any line, it will print the line to the user.