📄 ch07_08.htm
字号:
<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 7] 7.8 Highlighting in Shell Prompts </TITLE><METANAME="DC.title"CONTENT="UNIX Power Tools"><METANAME="DC.creator"CONTENT="Jerry Peek, Tim O'Reilly & Mike Loukides"><METANAME="DC.publisher"CONTENT="O'Reilly & Associates, Inc."><METANAME="DC.date"CONTENT="1998-08-04T21:33:50Z"><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="ch07_01.htm"TITLE="7. Setting Your Shell Prompt"><LINKREL="prev"HREF="ch07_07.htm"TITLE='7.7 A "Menu Prompt" for Naive Users'><LINKREL="next"HREF="ch07_09.htm"TITLE="7.9 Show Subshell Level with $SHLVL "></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="ch07_07.htm"TITLE='7.7 A "Menu Prompt" for Naive Users'><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT='Previous: 7.7 A "Menu Prompt" for Naive Users'BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 7<BR>Setting Your Shell Prompt</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch07_09.htm"TITLE="7.9 Show Subshell Level with $SHLVL "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 7.9 Show Subshell Level with $SHLVL "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-1330">7.8 Highlighting in Shell Prompts </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-6940"></A>If your prompt has some information that you want to stand out - or ifyou want your whole prompt to stand out from the rest of the text onthe screen - you might be able to make it in enhanced characters.If your terminal has special <SPANCLASS="link">escape sequences (<ACLASS="linkend"HREF="ch05_08.htm"TITLE="Terminal Escape Sequences ">5.8</A>)</SPAN>for enhancing the characters (and most do), you can use them to make partor all of your prompt stand out.</P><TABLECLASS="para.programreference"BORDER="1"><TR><THVALIGN="TOP"><ACLASS="programreference"HREF="examples/index.htm"TITLE="csh_init">csh_init</A><BR></TH><TDVALIGN="TOP">Let's say that you want to make sure people notice that they're loggedin as root (the superuser) by making part of the root prompt flash.Here are lines for the root <EMCLASS="emphasis">.cshrc</EM>: sh_init</TD></TR></TABLE><PCLASS="para"><TABLECLASS="screen.co"BORDER="1"><TR><THVALIGN="TOP"><PRECLASS="calloutlist"> <ACLASS="co"HREF="ch45_35.htm"TITLE="45.35 Using a Control Character in a Script ">echo...033</A> <ACLASS="co"HREF="ch50_07.htm"TITLE="50.7 How UNIX Systems Remember Their Name ">uname -n</A> </PRE></TH><TDVALIGN="TOP"><PRECLASS="screen"># Put ESCape character in $e. Use to start blinking mode (${e}[5m)# and go back to normal mode (${e}[0m) on VT100-series terminals:set e="`echo x | tr x \\033`"set prompt="${e}[5mroot${e}[0m@`uname -n`# "</PRE></TD></TR></TABLE></P><PCLASS="para">That prompt might look like this, with the word <CODECLASS="literal">root</CODE> flashing:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">root@sys.ora.com#</PRE></BLOCKQUOTE></P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-6956"></A><ACLASS="indexterm"NAME="AUTOID-6959"></A>The prompt is set inside double quotes (<CODECLASS="literal">"</CODE>), so the <CODECLASS="literal">uname -n</CODE>command is run once, when the <EMCLASS="emphasis">PS1</EM> string is first stored.In some shells, like <EMCLASS="emphasis">bash</EM> and <EMCLASS="emphasis">pdksh</EM>, you can put single quotes(<CODECLASS="literal">'</CODE>) around the <EMCLASS="emphasis">PS1</EM> string;this stores the backquotes (<CODECLASS="literal">`</CODE>) in the string, and the shell willinterpret them before it prints each prompt.(In this case, that's useless because the output of <CODECLASS="literal">uname -n</CODE>will always be the same.But if you want constantly updated information in your prompt, it'svery handy.)Article<ACLASS="xref"HREF="ch08_14.htm"TITLE="Bourne Shell Quoting ">8.14</A>tells more.</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-6973"></A>Because the same escape sequences won't work on all terminals, it's probably agood idea to add<SPANCLASS="link">an <EMCLASS="emphasis">if</EM> test (<ACLASS="linkend"HREF="ch47_03.htm"TITLE="Conditional Statements with if ">47.3</A>)</SPAN>that only sets the prompt if the terminal type<EMCLASS="emphasis">$TERM</EM> is in the Digital Equipment Corporation VT100 series (or one thatemulates it).<ACLASS="xref"HREF="ch07_08.htm#UPT-ART-1330-TAB-0"TITLE="VT100 Escape Sequences for Highlighting">Table 7.1</A>shows a few escape sequences for VT100 and compatible terminals.The <CODECLASS="literal">ESC</CODE> in each sequence stands for an ESCape character.<ACLASS="indexterm"NAME="AUTOID-6981"></A></P><TABLECLASS="table"><CAPTIONCLASS="table"><ACLASS="title"NAME="UPT-ART-1330-TAB-0">Table 7.1: VT100 Escape Sequences for Highlighting</A></CAPTION><THEADCLASS="thead"><TRCLASS="row"VALIGN="TOP"><THCLASS="entry"ALIGN="LEFT"ROWSPAN="1"COLSPAN="1">Sequence</TH><THCLASS="entry"ALIGN="LEFT"ROWSPAN="1"COLSPAN="1">What it Does</TH></TR></THEAD><TBODYCLASS="tbody"><TRCLASS="row"VALIGN="TOP"><TDCLASS="entry"ROWSPAN="1"COLSPAN="1"> ESC[1m</TD><TDCLASS="entry"ROWSPAN="1"COLSPAN="1">Bold, intensify foreground</TD></TR><TRCLASS="row"VALIGN="TOP"><TDCLASS="entry"ROWSPAN="1"COLSPAN="1"> ESC[4m</TD><TDCLASS="entry"ROWSPAN="1"COLSPAN="1">Underscore</TD></TR><TRCLASS="row"VALIGN="TOP"><TDCLASS="entry"ROWSPAN="1"COLSPAN="1"> ESC[5m</TD><TDCLASS="entry"ROWSPAN="1"COLSPAN="1">Blink</TD></TR><TRCLASS="row"VALIGN="TOP"><TDCLASS="entry"ROWSPAN="1"COLSPAN="1"> ESC[7m</TD><TDCLASS="entry"ROWSPAN="1"COLSPAN="1">Reverse video</TD></TR><TRCLASS="row"VALIGN="TOP"><TDCLASS="entry"ROWSPAN="1"COLSPAN="1"> ESC[0m</TD><TDCLASS="entry"ROWSPAN="1"COLSPAN="1">All attributes off</TD></TR></TBODY></TABLE><PCLASS="para">Of course, you can use different escape sequences if your terminal needsthem.<ACLASS="indexterm"NAME="AUTOID-7007"></A><ACLASS="indexterm"NAME="AUTOID-7009"></A>Better, read your terminal's <EMCLASS="emphasis">terminfo</EM> or <EMCLASS="emphasis">termcap</EM> databasewith a program like<SPANCLASS="link"><EMCLASS="emphasis">tput</EM> or <EMCLASS="emphasis">tcap</EM> (<ACLASS="linkend"HREF="ch41_10.htm"TITLE="Using terminfo Capabilities in Shell Programs ">41.10</A>)</SPAN>to get the correct escape sequences for your terminal.Store the escape sequences in<SPANCLASS="link">shell variables (<ACLASS="linkend"HREF="ch06_08.htm"TITLE="Shell Variables ">6.8</A>)</SPAN>.</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-7018"></A><ACLASS="indexterm"NAME="AUTOID-7020"></A><EMCLASS="emphasis">bash</EM> interprets octal character strings in the prompt.So you can simplify the two commands above into the version below.Change the backquotes (<CODECLASS="literal">`...`</CODE>) to<SPANCLASS="link"><CODECLASS="literal">$(</CODE> and <CODECLASS="literal">)</CODE> (<ACLASS="linkend"HREF="ch09_16.htm"TITLE="Command Substitution ">9.16</A>)</SPAN>if you want:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">PS1="\033[5mroot\033[0m@`uname -n`# "</PRE></BLOCKQUOTE></P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-7031"></A>Eight-bit-clean versions of <EMCLASS="emphasis">tcsh</EM> can put standout, boldface, andunderline - and any other terminal escape sequence, too - into yourshell prompt. For instance, <CODECLASS="literal">%S</CODE> starts standout mode and<CODECLASS="literal">%s</CODE> ends it; the <EMCLASS="emphasis">tcsh</EM> manpage has details for yourversion. </P><PCLASS="para">For example, to make the same prompt as above with the word<CODECLASS="literal">root</CODE> in standout mode (<EMCLASS="emphasis">tcsh</EM> puts the hostname into<CODECLASS="literal">%m</CODE>):</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">set prompt = '%Sroot%s@%m# '</PRE></BLOCKQUOTE></P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">JP</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="ch07_07.htm"TITLE='7.7 A "Menu Prompt" for Naive Users'><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT='Previous: 7.7 A "Menu Prompt" for Naive Users'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="ch07_09.htm"TITLE="7.9 Show Subshell Level with $SHLVL "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 7.9 Show Subshell Level with $SHLVL "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">7.7 A "Menu Prompt" for Naive Users</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">7.9 Show Subshell Level with $SHLVL </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 & 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 + -