An event designator is a reference to a command line entry in the history list. Unless the reference is absolute, events are relative to the current position in the history list.
Start a history substitution, except when followed by a space, tab,
the end of the line, ‘=’ or ‘(’ (when the
extglob shell option is enabled using the
Refer to command line n.
Refer to the command n lines back.
Refer to the previous command. This is a synonym for ‘!-1’.
Refer to the most recent command preceding the current position in the history list starting with string.
Refer to the most recent command preceding the current position in the history list containing string. The trailing ‘?’ may be omitted if the string is followed immediately by a newline.
Quick Substitution. Repeat the last command, replacing string1
with string2. Equivalent to
The entire command line typed so far.