ch48_04.htm

the unix power tools

></DT
><DD
CLASS="listitem"
><P
CLASS="para"
>This matches whatever comes before the date.
Match at the beginning of a line (<CODE
CLASS="literal"
>^</CODE
>) or (<CODE
CLASS="literal"
>|</CODE
>) match
a space, TAB, opening parenthesis, comma, or semicolon
(<CODE
CLASS="literal"
>[<IMG
SRC="../chars/squ.gif"
ALT=" ">T(,;]</CODE
>).
This keeps <EM
CLASS="emphasis"
>egrep</EM
> from matching other words that start with or
contain the month abbreviation <CODE
CLASS="literal"
>[Dd]ec</CODE
>.</P
></DD
><DT
CLASS="term"
><CODE
CLASS="literal"
>((([Dd]ec[^<IMG
SRC="../chars/squ.gif"
ALT=" ">T]*|\*)[<IMG
SRC="../chars/squ.gif"
ALT=" ">T]*|(012|12|\*)/)0*8)</CODE
></DT
><DD
CLASS="listitem"
><P
CLASS="para"
>This matches the date.
Match <EM
CLASS="emphasis"
>Dec</EM
> or <EM
CLASS="emphasis"
>dec</EM
> with zero or more of any character besides
space or TAB after
that (<CODE
CLASS="literal"
>[Dd]ec[^<IMG
SRC="../chars/squ.gif"
ALT=" ">T]*</CODE
>)-or (<CODE
CLASS="literal"
>|</CODE
>) have a literal asterisk
(<CODE
CLASS="literal"
>\*</CODE
>), which means &quot;match this on any month of the year.&quot;
Or (<CODE
CLASS="literal"
>|</CODE
>) match a numeric month like <EM
CLASS="emphasis"
>012</EM
> or <EM
CLASS="emphasis"
>12</EM
> or a literal
asterisk (<CODE
CLASS="literal"
>(012|12|\*)</CODE
>)-followed by a slash (<CODE
CLASS="literal"
>/</CODE
>).
Finally, you need today's date: it starts with any number of
zeros and ends with <EM
CLASS="emphasis"
>8</EM
> (<CODE
CLASS="literal"
>)0*8)</CODE
>).</P
></DD
><DT
CLASS="term"
><CODE
CLASS="literal"
>([^0123456789]|$)</CODE
></DT
><DD
CLASS="listitem"
><P
CLASS="para"
>The end of the expression matches lines anything except a
digit&nbsp;- or matches the end of the line.
This keeps <EM
CLASS="emphasis"
>egrep</EM
> from matching non-dates like <EM
CLASS="emphasis"
>8.75</EM
>.</P
></DD
></DL
><P
CLASS="para"
>Whew.
That expression is repeated for every other day that needs to be matched.
On Fridays, the output of <EM
CLASS="emphasis"
>/usr/lib/calendar</EM
> has four lines&nbsp;- one
each for Friday, Saturday, Sunday, and Monday.</P
></DIV
><DIV
CLASS="sect2"
><H3
CLASS="sect2"
><A
CLASS="title"
NAME="UPT-ART-3180-SECT-1.3"
>48.4.3 Automating Your Own Calendar </A
></H3
><P
CLASS="para"
>If you want a calendar every weekday, put a line like the following into
your
<SPAN
CLASS="link"
>personal <EM
CLASS="emphasis"
>crontab</EM
> file (<A
CLASS="linkend"
HREF="ch40_12.htm"
TITLE="Periodic Program Execution: The cron Facility "
>40.12</A
>)</SPAN
>.
We've split this onto two lines for printing, but you should type it all
on one line:</P
><P
CLASS="para"
><TABLE
CLASS="screen.co"
BORDER="1"
><TR
><TH
VALIGN="TOP"
><PRE
CLASS="calloutlist"
>
<A
CLASS="co"
HREF="ch06_03.htm"
TITLE="6.3 Predefined Environment Variables "
>$USER</A
> 
<A
CLASS="co"
HREF="ch44_09.htm"
TITLE="44.9 Testing Your Success "
>&amp;&amp;</A
> <A
CLASS="co"
HREF="ch13_01.htm"
TITLE="13.1 Using Standard Input and Output"
>&lt;</A
> </PRE
></TH
><TD
VALIGN="TOP"
><PRE
CLASS="screen"
>
<A
CLASS="indexterm"
NAME="AUTOID-57831"
></A
><A
CLASS="indexterm"
NAME="AUTOID-57834"
></A
><A
CLASS="indexterm"
NAME="AUTOID-57837"
></A
>6 6 * * 1-5 tf=/tmp/cal.$USER; umask 077; /bin/calendar &gt; $tf;
    test -s $tf &amp;&amp; mail -s 'Calendar for today' $USER &lt; $tf; rm -f $tf</PRE
></TD
></TR
></TABLE
></P
><P
CLASS="para"
>That runs <EM
CLASS="emphasis"
>calendar</EM
> from my home directory at
<SPAN
CLASS="link"
>6:06 a.m. (<A
CLASS="linkend"
HREF="ch40_05.htm"
TITLE="Avoiding Other at and cron Jobs "
>40.5</A
>)</SPAN
>
every weekday morning.
It sets a
<SPAN
CLASS="link"
>Bourne shell variable (<A
CLASS="linkend"
HREF="ch06_08.htm"
TITLE="Shell Variables "
>6.8</A
>)</SPAN
>
named <EM
CLASS="emphasis"
>tf</EM
> with the name of a temporary file in the
<SPAN
CLASS="link"
><EM
CLASS="emphasis"
>/tmp</EM
> directory (<A
CLASS="linkend"
HREF="ch21_03.htm"
TITLE="Unique Names for Temporary Files "
>21.3</A
>)</SPAN
>,
and sets a
<SPAN
CLASS="link"
><EM
CLASS="emphasis"
>umask</EM
> (<A
CLASS="linkend"
HREF="ch22_04.htm"
TITLE="Setting an Exact umask "
>22.4</A
>)</SPAN
>
to make the file private.
Then it runs <EM
CLASS="emphasis"
>calendar</EM
> and saves the output in the temporary file.
If there's a calendar for today, the <EM
CLASS="emphasis"
>mail</EM
> command sends the file
to me.
(The <EM
CLASS="emphasis"
>-s</EM
> option on our <EM
CLASS="emphasis"
>mail</EM
> command adds the <CODE
CLASS="literal"
>Subject:</CODE
>
line <EM
CLASS="emphasis"
>Calendar for today</EM
> to the message.
It isn't required.)
Finally, the temporary file is removed.</P
><P
CLASS="para"
><A
CLASS="indexterm"
NAME="AUTOID-57859"
></A
><A
CLASS="indexterm"
NAME="AUTOID-57862"
></A
><A
CLASS="indexterm"
NAME="AUTOID-57865"
></A
>If you don't have personal <EM
CLASS="emphasis"
>crontab</EM
>s, you can use a
<SPAN
CLASS="link"
>self-restarting <EM
CLASS="emphasis"
>at</EM
> job (<A
CLASS="linkend"
HREF="ch40_08.htm"
TITLE="Automatically Restarting at Jobs "
>40.8</A
>)</SPAN
>
and the
<SPAN
CLASS="link"
><EM
CLASS="emphasis"
>nextweekday</EM
> script (<A
CLASS="linkend"
HREF="ch40_10.htm"
TITLE="nextday, nextweekday: Tomorrow or Next Weekday "
>40.10</A
>)</SPAN
>
instead.<A
CLASS="indexterm"
NAME="AUTOID-57873"
></A
></P
></DIV
><DIV
CLASS="sect1info"
><P
CLASS="SECT1INFO"
>- <SPAN
CLASS="authorinitials"
>JP</SPAN
></P
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