Preg_match_all m Multi-line mode problem,

I'm going to match text in multiline mode

1.txt content is as follows
Hello
Qunide
Budui
Nihao
Goole

Eventually only matches the last Google

Multiline mode does not mean that each row matches ^$ then can you take out the matches for each row? It's supposed to match all the lines.
Why only match the last line, ask the great God ~ ~

Reply to discussion (solution)

Apparently you missed the check for the "enter" character of Windows.
That's right.
$pat = "#^[a-z0-9]+\r?$ #m";
Or
$pat = "#^[a-z0-9]+ #m";

