perl -e"BEGIN{$/=\(1024**2)  }" -pe "s/\x00\x42\x00\x11/\x00\x42\x00\xf0/sg" infile | perl -e"BEGIN{$/=\(1024**2-3)}" 
-pe "s/\x00\x42\x00\x11/\x00\x42\x00\xf0/sg" >outfile2

##</code><code>##

c:\test>type fred
1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890

##</code><code>##

c:\test>perl -e"BEGIN{$/=\10}" -pe" s[8901][abcd]" fred > joe

c:\test>type joe
1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890

##</code><code>##

c:\test>perl -e"BEGIN{$/=\10}" -pe" s[8901][abcd]g" fred | perl -e"BEGIN{$/=\7}" -pe"s[8901][abcd]g" >joe

##</code><code>##

c:\test>type joe
1234567abcd234567abcd2345678901234567abcd2345678901234567abcd2345678901234567abcd234567abcd2345678901234567abcd2345678901234567890