163 lines
3.4 KiB
HTML
163 lines
3.4 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
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<html>
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<head>
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<meta name="generator" content="HTML Tidy, see www.w3.org">
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<meta http-equiv="Content-Type" content=
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"text/html; charset=utf-8">
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<title>expr - Evaluate arguments as an expression</title>
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<LINK rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</HEAD>
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<body bgcolor="#FFFFFF">
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<!-- Java sync-link -->
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<SCRIPT LANGUAGE="Javascript" SRC="../rzahg/synch.js" TYPE="text/javascript"></SCRIPT>
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<h2>expr - Evaluate arguments as an expression</h2>
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<strong>Synopsis</strong>
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<p><strong>expr</strong> <em>operand ...</em></p>
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<p><strong>Description</strong></p>
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<p>The <strong>expr</strong> utility evaluates an expression formed
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by the <em>operands</em> and writes the result to standard
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output.</p>
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<p><strong>Operands</strong></p>
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<p>The format of the expression to evaluate is shown as follows.
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<em>expr</em>, <em>expr1</em>, and <em>expr2</em> can be decimal
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integers or strings.</p>
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<table>
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<tr>
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<td valign="top"><strong>Note:</strong></td>
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<td>The six relational expressions return the result of a decimal
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integer comparison if both arguments are integers. Otherwise, they
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return the result of a string comparison. The result of each
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comparison is 1 if the specified relationship is true, or 0 if the
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relationship is false.</td>
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</tr>
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</table>
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<table>
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<tr>
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<th align="left">Expression</th>
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<th align="left">Description</th>
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</tr>
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<tr>
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<td valign="top"><em>expr1</em> | <em>expr2</em></td>
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<td>Returns the evaluation of <em>expr1</em> if it is neither null
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nor zero; otherwise, returns the evaluation of <em>expr2</em>.</td>
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</tr>
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<tr>
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<td valign="top"><em>expr1</em> & <em>expr2</em></td>
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<td>Returns the evaluation of <em>expr1</em> if neither expression
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evaluates to null or zero; otherwise, returns zero.</td>
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</tr>
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<tr>
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<td><em>expr1</em> = <em>expr2</em></td>
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<td>Equal.</td>
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</tr>
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<tr>
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<td><em>expr1</em> > <em>expr2</em></td>
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<td>Greater than.</td>
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</tr>
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<tr>
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<td><em>expr1</em> >= <em>expr2</em></td>
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<td>Greater than or equal.</td>
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</tr>
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<tr>
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<td><em>expr1</em> < <em>expr2</em></td>
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<td>Less than.</td>
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</tr>
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<tr>
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<td><em>expr1</em> <= <em>expr2</em></td>
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<td>Less than or equal.</td>
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</tr>
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<tr>
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<td><em>expr1</em> != <em>expr2</em></td>
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<td>Not equal.</td>
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</tr>
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<tr>
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<td><em>expr1</em> + <em>expr2</em></td>
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<td>Addition of decimal integers.</td>
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</tr>
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<tr>
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<td><em>expr1</em> - <em>expr2</em></td>
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<td>Subtraction of decimal integers.</td>
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</tr>
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<tr>
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<td><em>expr1</em> * <em>expr2</em></td>
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<td>Multiplication of decimal integers.</td>
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</tr>
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<tr>
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<td><em>expr1</em> / <em>expr2</em></td>
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<td>Division of decimal integers.</td>
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</tr>
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<tr>
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<td><em>expr1</em> % <em>expr2</em></td>
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<td>Remainder of decimal integer division.</td>
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</tr>
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<tr>
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<td><em>expr1</em> : <em>expr2</em></td>
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<td>Matching expression.</td>
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</tr>
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<tr>
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<td>( <em>expr</em> )</td>
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<td>Grouping symbols.</td>
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</tr>
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</table>
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<p><strong>Exit Status</strong></p>
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<ul>
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<li>0 when the expression evaluates to neither null nor zero.</li>
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<li>1 when the expression evaluates to null or zero.</li>
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<li>2 when the expression is invalid.</li>
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<li>>2 when an error occurred.</li>
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</ul>
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<strong>Examples</strong>
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<ol>
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<li>Evaluate an arithmetic expression.
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<pre>
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expr 10+10*10/10-10
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</pre>
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</li>
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<li>Evaluate a true or false condition.
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<pre>
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expr 10 = 10
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</pre>
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</li>
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</ol>
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<!-- end ibmbody========================================================= -->
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</body>
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</html>
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