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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-r file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if the specified file is readable by the process</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-s file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if the specified file has a non-zero length</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-w file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if the file is writable by the process</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-x file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if the specified file is executable</FONT>







</TABLE><P>You use the test command's logical operators to combine integer, string, or file operators or to negate a single integer, string, or file operator. Table 26.5 lists the test command's logical operators.







<BR>







<BR>







<P ALIGN=CENTER>







<CENTER>







<FONT COLOR="#000080"><B>Table 26.5. Logical operators for the </B><B>test</B><B> command.</B></FONT></CENTER>







<BR>















<TABLE  BORDERCOLOR=#000040 BORDER=1 CELLSPACING=2 WIDTH="100%" CELLPADDING=2 >







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Command</I>







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Meaning</I></FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







! expr







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if expr is not true</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







expr1 -a expr2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if expr1 and expr2 are true</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







expr1 -o expr2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if expr1 or expr2 are true</FONT>







</TABLE><P>The tcsh shell does not have a test command, but tsch expressions perform the same function. The expression operators that tcsh supports are almost identical to those supported by the C language. You use these expressions mostly in if and while commands. Later in this chapter, the sections &quot;Using Conditional Statements&quot; and &quot;Using Iteration Statements&quot; cover these commands. Like the bash and pdksh test command, tcsh expressions support integer, string, file, and logical operators. Table 26.6 lists the integer operators supported by tcsh expressions.







<BR>







<BR>







<P ALIGN=CENTER>







<CENTER>







<FONT COLOR="#000080"><B>Table 26.6. Integer operators for </B><B>tcsh</B><B> expressions.</B></FONT></CENTER>







<BR>















<TABLE  BORDERCOLOR=#000040 BORDER=1 CELLSPACING=2 WIDTH="100%" CELLPADDING=2 >







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Operator</I>







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Meaning</I></FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







int1 &lt;= int2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if int1 is less than or equal to int2</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







int1 &gt;= int2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if int1 is greater than or equal to int2</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







int1 &lt; int2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if int1 is less than int2</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







int1 &gt; int2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if int1 is greater than int2</FONT>







</TABLE><P>Table 26.7 lists the string operators that tcsh expressions support.







<BR>







<BR>







<P ALIGN=CENTER>







<CENTER>







<FONT COLOR="#000080"><B>Table 26.7. String operators for </B><B>tcsh</B><B> expressions.</B></FONT></CENTER>







<BR>















<TABLE  BORDERCOLOR=#000040 BORDER=1 CELLSPACING=2 WIDTH="100%" CELLPADDING=2 >







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Operator</I>







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Meaning</I></FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







str1 == str2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if str1 is equal to str2</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







str1 != str2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if str1 is not equal to str2</FONT>







</TABLE><P>Table 26.8 lists the file operators that tcsh expressions support.







<BR>







<BR>







<P ALIGN=CENTER>







<CENTER>







<FONT COLOR="#000080"><B>Table 26.8. File operators for </B><B>tcsh</B><B> expressions.</B></FONT></CENTER>







<BR>















<TABLE  BORDERCOLOR=#000040 BORDER=1 CELLSPACING=2 WIDTH="100%" CELLPADDING=2 >







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Operator</I>







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Meaning</I></FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-r file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if file is readable</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-w file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if file is writable</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-x file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if file is executable</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-e file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if file exists</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-o file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if file is owned by the current user</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-z file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if file has a size of zero</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-f file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if file is a regular file</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







-d file







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if file is a directory file</FONT>







</TABLE><P>Table 26.9 lists the logical operators that tcsh expressions support are listed.







<BR>







<BR>







<P ALIGN=CENTER>







<CENTER>







<FONT COLOR="#000080"><B>Table 26.9. Logical operators for </B><B>tcsh</B><B> expressions.</B></FONT></CENTER>







<BR>















<TABLE  BORDERCOLOR=#000040 BORDER=1 CELLSPACING=2 WIDTH="100%" CELLPADDING=2 >







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Operator</I>







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







<I>Meaning</I></FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







exp1 || exp2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if exp1 is true or if exp2 is true</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







exp1 &amp;&amp; exp2







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if both exp1 and exp2 are true</FONT>







<TR>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







! exp







</FONT>







<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>







Returns true if exp is not true</FONT>







</TABLE><BR>







<A NAME="E68E145"></A>







<H3 ALIGN=CENTER>







<CENTER>







<FONT SIZE=5 COLOR="#FF0000"><B>Using Conditional Statements</B></FONT></CENTER></H3>







<BR>
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