[Help-bash] Why does TAB completion for something like abc*.txt expand to the first match?

[Peng Yu]

Hi,

If I have abc1.txt and abc2.txt in my current directory, when I type
'echo abc*.txt' and TAB in the command line, it will replace abc*.txt
with abc1.txt in one machine but will show both file names (with the
command 'echo abc*.txt' unchanged) in another machine. I'm not sure
what in bash controls this behavior. Could anybody let me know?
Thanks.

-- 
Regards,
Peng