Word Designators

Word designators are used to select desired words from the event. They are optional; if the word designator isn’t supplied, the history expansion uses the entire event. A ‘:’ separates the event specification from the word designator. It may be omitted if the word designator begins with a ‘^’, ‘$’, ‘*’, ‘-’, or ‘%’. Words are numbered from the beginning of the line, with the first word being denoted by 0 (zero). That first word is usually the command word, and the arguments begin with the second word. Words are inserted into the current line separated by single spaces.

For example,

!!

designates the preceding command. When you type this, the preceding command is repeated in toto.

!!:$

designates the last word of the preceding command. This may be shortened to !$.

!fi:2

designates the second argument of the most recent command starting with the letters fi.

Here are the word designators:

0 (zero)

The 0th word. For the shell, and many other, applications, this is the command word.

n

The nth word.

^

The first argument: word 1.

$

The last word. This is usually the last argument, but expands to the zeroth word if there is only one word in the line.

%

The first word matched by the most recent ‘?string?’ search, if the search string begins with a character that is part of a word. By default, searches begin at the end of each line and proceed to the beginning, so the first word matched is the one closest to the end of the line.

x-y

A range of words; ‘-y’ abbreviates ‘0-y’.

*

All of the words, except the 0th. This is a synonym for ‘1-$’. It is not an error to use ‘*’ if there is just one word in the event; it expands to the empty string in that case.

x*

Abbreviates ‘x-$’.

x-

Abbreviates ‘x-$’ like ‘x*’, but omits the last word. If ‘x’ is missing, it defaults to 0.

If a word designator is supplied without an event specification, the previous command is used as the event, equivalent to !!.