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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><HTML><HEAD><TITLE>Globbing</TITLE><METANAME="GENERATOR"CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+"><LINKREL="HOME"TITLE="Advanced Bash-Scripting Guide"HREF="index.html"><LINKREL="UP"TITLE="Regular Expressions"HREF="regexp.html"><LINKREL="PREVIOUS"TITLE="Regular Expressions"HREF="regexp.html"><LINKREL="NEXT"TITLE="Here Documents"HREF="here-docs.html"><METAHTTP-EQUIV="Content-Style-Type"CONTENT="text/css"><LINKREL="stylesheet"HREF="common/kde-common.css"TYPE="text/css"><METAHTTP-EQUIV="Content-Type"CONTENT="text/html; charset=iso-8859-1"><METAHTTP-EQUIV="Content-Language"CONTENT="en"><LINKREL="stylesheet"HREF="common/kde-localised.css"TYPE="text/css"TITLE="KDE-English"><LINKREL="stylesheet"HREF="common/kde-default.css"TYPE="text/css"TITLE="KDE-Default"></HEAD><BODYCLASS="SECT1"BGCOLOR="#FFFFFF"TEXT="#000000"LINK="#AA0000"VLINK="#AA0055"ALINK="#AA0000"STYLE="font-family: sans-serif;"><DIVCLASS="NAVHEADER"><TABLESUMMARY="Header navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><THCOLSPAN="3"ALIGN="center">Advanced Bash-Scripting Guide: An in-depth exploration of the art of shell scripting</TH></TR><TR><TDWIDTH="10%"ALIGN="left"VALIGN="bottom"><AHREF="regexp.html"ACCESSKEY="P">Prev</A></TD><TDWIDTH="80%"ALIGN="center"VALIGN="bottom">Chapter 17. Regular Expressions</TD><TDWIDTH="10%"ALIGN="right"VALIGN="bottom"><AHREF="here-docs.html"ACCESSKEY="N">Next</A></TD></TR></TABLE><HRALIGN="LEFT"WIDTH="100%"></DIV><DIVCLASS="SECT1"><H1CLASS="SECT1"><ANAME="GLOBBINGREF"></A>17.2. Globbing</H1><P><ANAME="GLOBBINGREF2"></A></P><P>Bash itself cannot recognize Regular Expressions. Inside scripts, it is commands and utilities -- such as <AHREF="sedawk.html#SEDREF">sed</A> and <AHREF="awk.html#AWKREF">awk</A> -- that interpret RE's.</P><P>Bash <SPANCLASS="emphasis"><ICLASS="EMPHASIS">does</I></SPAN> carry out <ICLASS="FIRSTTERM">filename expansion</I> <ANAME="AEN16210"HREF="#FTN.AEN16210">[1]</A> -- a process known as <ICLASS="FIRSTTERM">globbing</I> -- but this does <SPANCLASS="emphasis"><ICLASS="EMPHASIS">not</I></SPAN> use the standard RE set. Instead, globbing recognizes and expands wild cards. Globbing interprets the standard wild card characters, <SPANCLASS="TOKEN">*</SPAN> and <SPANCLASS="TOKEN">?</SPAN>, character lists in square brackets, and certain other special characters (such as <SPANCLASS="TOKEN">^</SPAN> for negating the sense of a match). There are important limitations on wild card characters in globbing, however. Strings containing <TTCLASS="REPLACEABLE"><I>*</I></TT> will not match filenames that start with a dot, as, for example, <TTCLASS="FILENAME">.bashrc</TT>. <ANAME="AEN16223"HREF="#FTN.AEN16223">[2]</A> Likewise, the <TTCLASS="REPLACEABLE"><I>?</I></TT> has a different meaning in globbing than as part of an RE.</P><P> <TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="SCREEN"> <TTCLASS="PROMPT">bash$ </TT><TTCLASS="USERINPUT"><B>ls -l</B></TT> <TTCLASS="COMPUTEROUTPUT">total 2 -rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 a.1 -rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 b.1 -rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 c.1 -rw-rw-r-- 1 bozo bozo 466 Aug 6 17:48 t2.sh -rw-rw-r-- 1 bozo bozo 758 Jul 30 09:02 test1.txt</TT> <TTCLASS="PROMPT">bash$ </TT><TTCLASS="USERINPUT"><B>ls -l t?.sh</B></TT> <TTCLASS="COMPUTEROUTPUT">-rw-rw-r-- 1 bozo bozo 466 Aug 6 17:48 t2.sh</TT> <TTCLASS="PROMPT">bash$ </TT><TTCLASS="USERINPUT"><B>ls -l [ab]*</B></TT> <TTCLASS="COMPUTEROUTPUT">-rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 a.1 -rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 b.1</TT> <TTCLASS="PROMPT">bash$ </TT><TTCLASS="USERINPUT"><B>ls -l [a-c]*</B></TT> <TTCLASS="COMPUTEROUTPUT">-rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 a.1 -rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 b.1 -rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 c.1</TT> <TTCLASS="PROMPT">bash$ </TT><TTCLASS="USERINPUT"><B>ls -l [^ab]*</B></TT> <TTCLASS="COMPUTEROUTPUT">-rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 c.1 -rw-rw-r-- 1 bozo bozo 466 Aug 6 17:48 t2.sh -rw-rw-r-- 1 bozo bozo 758 Jul 30 09:02 test1.txt</TT> <TTCLASS="PROMPT">bash$ </TT><TTCLASS="USERINPUT"><B>ls -l {b*,c*,*est*}</B></TT> <TTCLASS="COMPUTEROUTPUT">-rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 b.1 -rw-rw-r-- 1 bozo bozo 0 Aug 6 18:42 c.1 -rw-rw-r-- 1 bozo bozo 758 Jul 30 09:02 test1.txt</TT> </PRE></TD></TR></TABLE> </P><P>Bash performs filename expansion on unquoted command-line arguments. The <AHREF="internal.html#ECHOREF">echo</A> command demonstrates this.</P><P> <TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="SCREEN"> <TTCLASS="PROMPT">bash$ </TT><TTCLASS="USERINPUT"><B>echo *</B></TT> <TTCLASS="COMPUTEROUTPUT">a.1 b.1 c.1 t2.sh test1.txt</TT> <TTCLASS="PROMPT">bash$ </TT><TTCLASS="USERINPUT"><B>echo t*</B></TT> <TTCLASS="COMPUTEROUTPUT">t2.sh test1.txt</TT> </PRE></TD></TR></TABLE> </P><DIVCLASS="NOTE"><TABLECLASS="NOTE"WIDTH="100%"BORDER="0"><TR><TDWIDTH="25"ALIGN="CENTER"VALIGN="TOP"><IMGSRC="common/note.png"HSPACE="5"ALT="Note"></TD><TDALIGN="LEFT"VALIGN="TOP"><P>It is possible to modify the way Bash interprets special characters in globbing. A <BCLASS="COMMAND">set -f</B> command disables globbing, and the <TTCLASS="OPTION">nocaseglob</TT> and <TTCLASS="OPTION">nullglob</TT> options to <AHREF="internal.html#SHOPTREF">shopt</A> change globbing behavior.</P></TD></TR></TABLE></DIV><P>See also <AHREF="loops.html#LISTGLOB">Example 10-4</A>.</P></DIV><H3CLASS="FOOTNOTES">Notes</H3><TABLEBORDER="0"CLASS="FOOTNOTES"WIDTH="100%"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="5%"><ANAME="FTN.AEN16210"HREF="globbingref.html#AEN16210">[1]</A></TD><TDALIGN="LEFT"VALIGN="TOP"WIDTH="95%"><P><ICLASS="FIRSTTERM">Filename expansion</I> means expanding filename patterns or templates containing special characters. For example, <TTCLASS="FILENAME">example.???</TT> might expand to <TTCLASS="FILENAME">example.001</TT> and/or <TTCLASS="FILENAME">example.txt</TT>.</P></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="5%"><ANAME="FTN.AEN16223"HREF="globbingref.html#AEN16223">[2]</A></TD><TDALIGN="LEFT"VALIGN="TOP"WIDTH="95%"><P> Filename expansion <SPANCLASS="emphasis"><ICLASS="EMPHASIS">can</I></SPAN> match dotfiles, but only if the pattern explicitly includes the dot as a literal character. <TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING"> 1 ~/[.]bashrc # Will not expand to ~/.bashrc 2 ~/?bashrc # Neither will this. 3 # Wild cards and metacharacters will NOT 4 #+ expand to a dot in globbing. 5 6 ~/.[b]ashrc # Will expand to ~/.bashrc 7 ~/.ba?hrc # Likewise. 8 ~/.bashr* # Likewise. 9 10 # Setting the "dotglob" option turns this off. 11 12 # Thanks, S.C.</PRE></TD></TR></TABLE> </P></TD></TR></TABLE><DIVCLASS="NAVFOOTER"><HRALIGN="LEFT"WIDTH="100%"><TABLESUMMARY="Footer navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top"><AHREF="regexp.html"ACCESSKEY="P">Prev</A></TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="index.html"ACCESSKEY="H">Home</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top"><AHREF="here-docs.html"ACCESSKEY="N">Next</A></TD></TR><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top">Regular Expressions</TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="regexp.html"ACCESSKEY="U">Up</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top">Here Documents</TD></TR></TABLE></DIV></BODY></HTML>⌨️ 快捷键说明
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