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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 51] 51.7 When You Get Impatient </TITLE><METANAME="DC.title"CONTENT="UNIX Power Tools"><METANAME="DC.creator"CONTENT="Jerry Peek, Tim O'Reilly &amp; Mike Loukides"><METANAME="DC.publisher"CONTENT="O'Reilly &amp; Associates, Inc."><METANAME="DC.date"CONTENT="1998-08-04T21:57:25Z"><METANAME="DC.type"CONTENT="Text.Monograph"><METANAME="DC.format"CONTENT="text/html"SCHEME="MIME"><METANAME="DC.source"CONTENT="1-56592-260-3"SCHEME="ISBN"><METANAME="DC.language"CONTENT="en-US"><METANAME="generator"CONTENT="Jade 1.1/O'Reilly DocBook 3.0 to HTML 4.0"><LINKREV="made"HREF="mailto:online-books@oreilly.com"TITLE="Online Books Comments"><LINKREL="up"HREF="ch51_01.htm"TITLE="51. Miscellaneous Useful Programs and Curiosities"><LINKREL="prev"HREF="ch51_06.htm"TITLE="51.6 Cleaning script Files "><LINKREL="next"HREF="ch51_08.htm"TITLE="51.8 Type Bang Splat.  Don't Forget the Rabbit Ears "></HEAD><BODYBGCOLOR="#FFFFFF"TEXT="#000000"><DIVCLASS="htmlnav"><H1><IMGSRC="gifs/smbanner.gif"ALT="UNIX Power Tools"USEMAP="#srchmap"BORDER="0"></H1><MAPNAME="srchmap"><AREASHAPE="RECT"COORDS="0,0,466,58"HREF="index.htm"ALT="UNIX Power Tools"><AREASHAPE="RECT"COORDS="467,0,514,18"HREF="jobjects/fsearch.htm"ALT="Search this book"></MAP><TABLEWIDTH="515"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch51_06.htm"TITLE="51.6 Cleaning script Files "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 51.6 Cleaning script Files "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 51<BR>Miscellaneous Useful Programs and Curiosities</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch51_08.htm"TITLE="51.8 Type Bang Splat.  Don't Forget the Rabbit Ears "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 51.8 Type Bang Splat.  Don't Forget the Rabbit Ears "BORDER="0"></A></TD></TR></TABLE>&nbsp;<HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-9001">51.7 When You Get Impatient </A></H2><TABLECLASS="para.programreference"BORDER="1"><TR><THVALIGN="TOP"><ACLASS="programreference"HREF="examples/index.htm"TITLE="vis">vis</A><BR></TH><TDVALIGN="TOP"><ACLASS="indexterm"NAME="AUTOID-60238"></A><ACLASS="indexterm"NAME="AUTOID-60241"></A><ACLASS="indexterm"NAME="AUTOID-60244"></A><ACLASS="indexterm"NAME="AUTOID-60246"></A><ACLASS="indexterm"NAME="AUTOID-60249"></A>Sometimes you find yourself repeating the same commandover and over again&nbsp;- for example, <SPANCLASS="link"><EMCLASS="emphasis">ps</EM> (<ACLASS="linkend"HREF="ch38_05.htm"TITLE="The ps Command ">38.5</A>)</SPAN>to monitor theprogress of your background processes, or <SPANCLASS="link"><EMCLASS="emphasis">lpq</EM> (<ACLASS="linkend"HREF="ch43_02.htm"TITLE="Introduction to Printing on UNIX ">43.2</A>)</SPAN>to knowwhen your printout is finished.Instead of typing thesame command repeatedly, or even using C shell <SPANCLASS="link">history (<ACLASS="linkend"HREF="ch11_01.htm#UPT-ART-4920"TITLE="The Lessons of History ">11.1</A>)</SPAN>to repeat it, use the <EMCLASS="emphasis">vis</EM> command.For example:</TD></TR></TABLE><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>vis ps</B></CODE></PRE></BLOCKQUOTE></P><PCLASS="para">The <EMCLASS="emphasis">vis</EM> command takes over your screenand shows the output of the initial <EMCLASS="emphasis">ps</EM> command.Every 15seconds, the command is executed again and your screen isupdated with the newinformation. If this delay is too long for you, you can get <EMCLASS="emphasis">vis</EM><ACLASS="indexterm"NAME="AUTOID-60266"></A>to use a shorter delay using the <EMCLASS="emphasis">-d</EM> option:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>vis -d 2 ps</B></CODE></PRE></BLOCKQUOTE></P><PCLASS="para">The information will now be updated every 2 seconds.Your screen is cleared and you are shown the output of <EMCLASS="emphasis">ps</EM>.On the top line, <EMCLASS="emphasis">vis</EM> tells you the command being run,how long your delay is (if not the default), and how many timesit has been executed.The <CODECLASS="literal">Exec:</CODE> line is incrementedevery time the command is repeated.</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">Command:  ps                      Delay:  2            Exec:  1  PID TT STAT  TIME COMMAND 2971 p1 S     0:06 -sh (csh) 6139 p1 S     0:00 vis -d 2 ps 6145 p1 R     0:00 ps 3401 q0 IW    0:13 -sh (csh) 5954 q0 S     0:01 vi ch0114019 q5 IW    0:02 -sh (csh)29380 r7 IW    0:00 -bin/csh (csh)29401 rd IW    0:00 -bin/csh (csh)</PRE></BLOCKQUOTE></P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-60280"></A><EMCLASS="emphasis">vis</EM> provides a few other command-line options. The <EMCLASS="emphasis">-s</EM> option is particularly neat&nbsp;- using <EMCLASS="emphasis">-s</EM>, any lines that have changed since the last iteration areprinted in standout mode.</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-60287"></A><ACLASS="indexterm"NAME="AUTOID-60289"></A><ACLASS="indexterm"NAME="AUTOID-60291"></A><ACLASS="indexterm"NAME="AUTOID-60293"></A><ACLASS="indexterm"NAME="AUTOID-60296"></A><ACLASS="indexterm"NAME="AUTOID-60299"></A>Note that variations of this command have floated around in the public domain under several different names, such as <EMCLASS="emphasis">display</EM>, <EMCLASS="emphasis">rep</EM>, and <EMCLASS="emphasis">watch</EM>. We found <EMCLASS="emphasis">vis</EM> to be the most useful.</P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">LM</SPAN></P></DIV></DIV><DIVCLASS="htmlnav"><P></P><HRALIGN="LEFT"WIDTH="515"TITLE="footer"><TABLEWIDTH="515"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch51_06.htm"TITLE="51.6 Cleaning script Files "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 51.6 Cleaning script Files "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><ACLASS="book"HREF="index.htm"TITLE="UNIX Power Tools"><IMGSRC="gifs/txthome.gif"SRC="gifs/txthome.gif"ALT="UNIX Power Tools"BORDER="0"></A></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch51_08.htm"TITLE="51.8 Type Bang Splat.  Don't Forget the Rabbit Ears "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 51.8 Type Bang Splat.  Don't Forget the Rabbit Ears "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">51.6 Cleaning script Files </TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><ACLASS="index"HREF="index/idx_0.htm"TITLE="Book Index"><IMGSRC="gifs/index.gif"SRC="gifs/index.gif"ALT="Book Index"BORDER="0"></A></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172">51.8 Type Bang Splat.  Don't Forget the Rabbit Ears </TD></TR></TABLE><HRALIGN="LEFT"WIDTH="515"TITLE="footer"><IMGSRC="gifs/smnavbar.gif"SRC="gifs/smnavbar.gif"USEMAP="#map"BORDER="0"ALT="The UNIX CD Bookshelf Navigation"><MAPNAME="map"><AREASHAPE="RECT"COORDS="0,0,73,21"HREF="../index.htm"ALT="The UNIX CD Bookshelf"><AREASHAPE="RECT"COORDS="74,0,163,21"HREF="index.htm"ALT="UNIX Power Tools"><AREASHAPE="RECT"COORDS="164,0,257,21"HREF="../unixnut/index.htm"ALT="UNIX in a Nutshell"><AREASHAPE="RECT"COORDS="258,0,321,21"HREF="../vi/index.htm"ALT="Learning the vi Editor"><AREASHAPE="RECT"COORDS="322,0,378,21"HREF="../sedawk/index.htm"ALT="sed &amp; awk"><AREASHAPE="RECT"COORDS="379,0,438,21"HREF="../ksh/index.htm"ALT="Learning the Korn Shell"><AREASHAPE="RECT"COORDS="439,0,514,21"HREF="../lrnunix/index.htm"ALT="Learning the UNIX Operating System"></MAP></DIV></BODY></HTML>
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