#!/usr/bin/perl

print "hello\n";
$find_image = 1;

$line = " ALT=\"$\mathcal{L}_{EM}=-\frac{m}{\gamma V}-\frac{q}{c^{2}V}\frac{U^{\mu }}{\gamma }A_{\mu }-\frac{1}{4c^{2}}(A^{\mu ,\nu }-A^{\nu ,\mu })(A_{\mu ,\nu }-A_{\nu ,\mu })$\"> ";

($find_image and ($line =~ /ALT/))?
  print "found alt\n":
  print "NOT found\n";

$line =~ s/ALT=\".*/ALT=\"fred\" >/s;

print "$line\n";