📄 ch38_07.htm

📁 the unix power tools
💻 HTM
字号:
<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 38] 38.7 Why ps Prints Some Commands in Parentheses </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="1998-08-04T21:49:41Z"><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="ch38_01.htm"TITLE="38. Starting, Stopping, and Killing Processes"><LINKREL="prev"HREF="ch38_06.htm"TITLE="38.6 The Controlling Terminal "><LINKREL="next"HREF="ch38_08.htm"TITLE="38.8 What Are Signals? "></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="ch38_06.htm"TITLE="38.6 The Controlling Terminal "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 38.6 The Controlling Terminal "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 38<BR>Starting, Stopping, and Killing Processes</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch38_08.htm"TITLE="38.8 What Are Signals? "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 38.8 What Are Signals? "BORDER="0"></A></TD></TR></TABLE>&nbsp;<HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-0362">38.7 Why ps Prints Some Commands in Parentheses </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-42785"></A><ACLASS="indexterm"NAME="AUTOID-42788"></A><ACLASS="indexterm"NAME="AUTOID-42791"></A>The reason that some versions of <EMCLASS="emphasis">ps</EM>,and thus derivatives such as <EMCLASS="emphasis">w</EM>,sometimes print commandsin parentheses [one of our UNIX systems uses square brackets<EMCLASS="emphasis">-JP</EM>&nbsp;]:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>ps -f -u jerry</B></CODE>     UID   PID  PPID  C    STIME TTY      TIME COMMAND   jerry 29240 29235  0 07:56:19 ttyp1    0:01 sh find_mh_dupes    jerry 29259 29240 23 07:57:52 ttyp1    0:07 (egrep)</PRE></BLOCKQUOTE></P><PCLASS="para">is that whoever wrote <EMCLASS="emphasis">ps</EM> liked it that way. Theparentheses indicate that the command overwrote its name,or that <EMCLASS="emphasis">ps</EM> could not find the name, and that <EMCLASS="emphasis">ps</EM>is printing instead the &quot;accounting name.&quot; (The accounting nameis the last component of the name given to the<SPANCLASS="link"><EMCLASS="emphasis">exec</EM> (<ACLASS="linkend"HREF="ch38_02.htm"TITLE="fork and exec ">38.2</A>)</SPAN>system call,and is the name used in the system resource usage accounting file.)Basically, <EMCLASS="emphasis">ps</EM> does this[in the C language<EMCLASS="emphasis">-JP</EM>&nbsp;]:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">if (proc-&gt;argv == NULL || strcmp(proc-&gt;acct_name, proc-&gt;argv[0]) != 0)   printf(&quot;(%s)&quot;, proc-&gt;acct_name);</PRE></BLOCKQUOTE></P><PCLASS="para">In the case of a large environment,<EMCLASS="emphasis">ps</EM> is unable to find the argument vector.This is because it reads only the last few stack pages of each process.</P><PCLASS="para">Other versions of <EMCLASS="emphasis">ps</EM> use completely different mechanismsfor locating the command arguments and may never print parentheses.</P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">CT</SPAN> <SPANCLASS="bibliomisc">in <ACLASS="systemitem.newsgroup"HREF="news:net.unix-wizards">net.unix-wizards</A> on Usenet, 13 November 1983</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="ch38_06.htm"TITLE="38.6 The Controlling Terminal "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 38.6 The Controlling Terminal "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="ch38_08.htm"TITLE="38.8 What Are Signals? "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 38.8 What Are Signals? "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">38.6 The Controlling Terminal </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">38.8 What Are Signals? </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>
⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -