ch31_04.htm

the unix power tools

> on a line will change it to
have <CODE
CLASS="literal"
>H4</CODE
>.
Move through your file (maybe with a search: <CODE
CLASS="literal"
>/STRONG</CODE
> ...
<CODE
CLASS="literal"
>n</CODE
> ...), typing <CODE
CLASS="literal"
>@a</CODE
> or <CODE
CLASS="literal"
>@b</CODE
> as you go.
Or use <CODE
CLASS="literal"
>@@</CODE
> to make the same change you made on a previous line.</P
></DIV
><DIV
CLASS="sect2"
><H3
CLASS="sect2"
><A
CLASS="title"
NAME="UPT-ART-9913-SECT-1.2"
>31.4.2 Combining @-Functions </A
></H3
><P
CLASS="para"
>An <CODE
CLASS="literal"
>@</CODE
>-function can execute other <CODE
CLASS="literal"
>@</CODE
>-functions.
For example, here are four lines ready for storing as <CODE
CLASS="literal"
>@a</CODE
> through
<CODE
CLASS="literal"
>@d</CODE
>:</P
><P
CLASS="para"
><BLOCKQUOTE
CLASS="screen"
><PRE
CLASS="screen"
>0l@c$T/@c   <I
CLASS="lineannotation"
>...becomes @a</I
>
0l@d$T/@d   <I
CLASS="lineannotation"
>...becomes @b</I
>
cwH3^[   <I
CLASS="lineannotation"
>...becomes @c</I
>
cwH4^[   <I
CLASS="lineannotation"
>...becomes @d</I
></PRE
></BLOCKQUOTE
></P
><P
CLASS="para"
>See that the definition of <CODE
CLASS="literal"
>@a</CODE
> has <CODE
CLASS="literal"
>@c</CODE
> in it twice?
When you execute <CODE
CLASS="literal"
>@a</CODE
>, it will do <CODE
CLASS="literal"
>0l</CODE
> to move to the
second character on the line, then do <CODE
CLASS="literal"
>@c</CODE
> to change the word
to <CODE
CLASS="literal"
>H3</CODE
>, move to the end of the line and use <CODE
CLASS="literal"
>@c</CODE
> again.
Calling one <CODE
CLASS="literal"
>@</CODE
>-function from another can save re-typing
repetitive commands.</P
><P
CLASS="para"
>A disadvantage is that <CODE
CLASS="literal"
>@@</CODE
> won't always work as you might expect.
If you type <CODE
CLASS="literal"
>@a</CODE
> to make a change in one place,
then move somewhere else and type <CODE
CLASS="literal"
>@@</CODE
>, the <CODE
CLASS="literal"
>@@</CODE
> will
do what <CODE
CLASS="literal"
>@c</CODE
> does (instead of what you might have wanted,
<CODE
CLASS="literal"
>@a</CODE
>).
That's because the <CODE
CLASS="literal"
>@a</CODE
> function finishes by doing a <CODE
CLASS="literal"
>@c</CODE
>.</P
></DIV
><DIV
CLASS="sect2"
><H3
CLASS="sect2"
><A
CLASS="title"
NAME="UPT-ART-9913-SECT-1.3"
>31.4.3 Reusing a Definition </A
></H3
><P
CLASS="para"
>You don't have to delete the definition line into a buffer with <CODE
CLASS="literal"
>dd</CODE
>.
If you think you might need to fine-tune the command, you can yank
(copy) it into a buffer with a command like <CODE
CLASS="literal"
>&quot;ay$</CODE
>.
Then, if you need to revise the command, re-edit the line and type
<CODE
CLASS="literal"
>&quot;ay$</CODE
> to put the revised version into the buffer.
Or use <CODE
CLASS="literal"
>&quot;by$</CODE
> to copy the revised line into another buffer.</P
></DIV
><DIV
CLASS="sect2"
><H3
CLASS="sect2"
><A
CLASS="title"
NAME="UPT-ART-9913-SECT-1.4"
>31.4.4 Newlines in an @-Function </A
></H3
><P
CLASS="para"
>Stored <CODE
CLASS="literal"
>@</CODE
>-functions can span multiple lines.
For example, if you delete the following four lines with <CODE
CLASS="literal"
>&quot;z4dd</CODE
>,
typing <CODE
CLASS="literal"
>@z</CODE
> will open a new line below (<CODE
CLASS="literal"
>o</CODE
>) and
insert four new lines of text:</P
><P
CLASS="para"
><BLOCKQUOTE
CLASS="screen"
><PRE
CLASS="screen"
>oThis is the new line one.
This is the new line two.
This is the third line.
This is the fourth.^[</PRE
></BLOCKQUOTE
></P
><P
CLASS="para"
>After you execute the function with <CODE
CLASS="literal"
>@z</CODE
>,
your cursor will move to the line below the new fourth line.
Why?
Because you included the newlines (RETURNs) in the buffer; each
RETURN moves down a line&nbsp;- including the RETURN after the
last ESC.</P
><P
CLASS="para"
>If you don't want that, there are two ways to fix it:</P
><UL
CLASS="itemizedlist"
><LI
CLASS="listitem"
><P
CLASS="para"
>Delete the first three lines, including the newlines, into the buffer
by typing <CODE
CLASS="literal"
>&quot;z3dd</CODE
>.
Delete the fourth line, without its newline, and <EM
CLASS="emphasis"
>append</EM
> it to
the buffer by typing <CODE
CLASS="literal"
>&quot;ZD</CODE
>.
(An uppercase letter like <CODE
CLASS="literal"
>Z</CODE
> appends to a named buffer.
<CODE
CLASS="literal"
>D</CODE
> deletes all of a line except the newline.)</P
><P
CLASS="para"
>Some versions of <EM
CLASS="emphasis"
>vi</EM
> will delete four lines, without the last
newline, when you use <CODE
CLASS="literal"
>&quot;z4D</CODE
>.</P
></LI
><LI
CLASS="listitem"
><P
CLASS="para"
>Type all of the text onto a single line; embed the newlines in
that line by typing <KBD
CLASS="keycap"
>[CTRL-v]</KBD
> <KBD
CLASS="keycap"
>[RETURN]</KBD
>
between each finished line.
It'll look like this:</P
><P
CLASS="para"
><BLOCKQUOTE
CLASS="screen"
><PRE
CLASS="screen"
>oThis is the new line one.^MThis is the new line two.^MThis is the new...</PRE
></BLOCKQUOTE
></P
><P
CLASS="para"
>Delete that long line into your buffer with <CODE
CLASS="literal"
>&quot;zD</CODE
>.
Because <CODE
CLASS="literal"
>D</CODE
> doesn't delete the final newline, your cursor will
stay at the end of the fourth new line after you execute the <CODE
CLASS="literal"
>@z</CODE
>.</P
></LI
></UL
><A
CLASS="indexterm"
NAME="AUTOID-35196"
></A
><A
CLASS="indexterm"
NAME="AUTOID-35197"
></A
></DIV
><DIV
CLASS="sect1info"
><P
CLASS="SECT1INFO"
>- <SPAN
CLASS="authorinitials"
>JP</SPAN
></P
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