In my Centos linux terminal, if I press up on the arrow keys to bring up a previous command, specifically a long one, and then try to delete it using backspace, it won't delete the entire command. I have to use ctrl+c to bring up another line since I can't delete it. The thing I noticed is if I delete as much as I can on the line and enter a valid command, it still runs it.
For example, say I bring up a previous command and now my terminal line looks like
[user@centos]$ sudo mount -t iso9660 -o loop nameoffile.iso /mnt/mntpnt
I start "backspacing" but can't delete everything so now it's just
[user@centos]$ sudo mount
but if I type a command such as pwd
[user@centos]$ sudo mountpwd
it will execute the command and list my current directory.