>bash --version GNU bash, version 4.3.48(1)-release (x86_64-slackware-linux-gnu) Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software; you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. >echo with some arguments ! with some arguments ! >foo with some arguments ! -bash: foo: command not found >'!' foo -bash: !: command not found >! foo -bash: foo: command not found >