ch09_01.htm

By Tom Christiansen and Nathan Torkington ISBN 1-56592-243-3 First Edition, published August 1998

CLASS="entry"
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><P
CLASS="para"
>5</P
></TD
><TD
CLASS="entry"
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><P
CLASS="para"
>gid</P
></TD
><TD
CLASS="entry"
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><P
CLASS="para"
>Numeric group ID of file's owner</P
></TD
></TR
><TR
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><TD
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><P
CLASS="para"
>6</P
></TD
><TD
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><P
CLASS="para"
>rdev</P
></TD
><TD
CLASS="entry"
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><P
CLASS="para"
>The device identifier (special files only)</P
></TD
></TR
><TR
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><TD
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><P
CLASS="para"
>7</P
></TD
><TD
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><P
CLASS="para"
>size</P
></TD
><TD
CLASS="entry"
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><P
CLASS="para"
>Total size of file, in bytes</P
></TD
></TR
><TR
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><TD
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><P
CLASS="para"
>8</P
></TD
><TD
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><P
CLASS="para"
>atime</P
></TD
><TD
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><P
CLASS="para"
>Last access time, in seconds, since the Epoch</P
></TD
></TR
><TR
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><TD
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><P
CLASS="para"
>9</P
></TD
><TD
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><P
CLASS="para"
>mtime</P
></TD
><TD
CLASS="entry"
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COLSPAN="1"
><P
CLASS="para"
>Last modify time, in seconds, since the Epoch</P
></TD
></TR
><TR
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><TD
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><P
CLASS="para"
>10</P
></TD
><TD
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><P
CLASS="para"
>ctime</P
></TD
><TD
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><P
CLASS="para"
>Inode change time, in seconds, since the Epoch</P
></TD
></TR
><TR
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><TD
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><P
CLASS="para"
>11</P
></TD
><TD
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><P
CLASS="para"
>blksize</P
></TD
><TD
CLASS="entry"
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><P
CLASS="para"
>Preferred block size for filesystem I/O</P
></TD
></TR
><TR
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><TD
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><P
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>12</P
></TD
><TD
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><P
CLASS="para"
>blocks</P
></TD
><TD
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><P
CLASS="para"
>Actual number of blocks allocated</P
></TD
></TR
></TBODY
></TABLE
><P
CLASS="para"
>The standard <A
CLASS="indexterm"
NAME="ch09-idx-1000005421-0"
></A
>File::stat module provides a named interface to these values. It overrides the <CODE
CLASS="literal"
>stat</CODE
> function, so instead of returning the preceding array, it returns an object with a method for each attribute:</P
><PRE
CLASS="programlisting"
>use File::stat;

$inode = stat(&quot;/usr/bin/vi&quot;);
$ctime = $inode-&gt;ctime;
$size  = $inode-&gt;size;</PRE
><P
CLASS="para"
>In addition, Perl provides a set of operators that call <CODE
CLASS="literal"
>stat</CODE
> and return one value only. These are collectively referred to as the <A
CLASS="indexterm"
NAME="ch09-idx-1000004344-0"
></A
>-X operators because they all take the form of a dash followed by a single character. They're modelled on the shell's <EM
CLASS="emphasis"
>test</EM
> operators:</P
><TABLE
CLASS="informaltable"
BORDER="1"
CELLPADDING="3"
><THEAD
CLASS="thead"
><TR
CLASS="row"
VALIGN="TOP"
><TH
CLASS="entry"
ALIGN="LEFT"
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><P
CLASS="para"
>-X</P
></TH
><TH
CLASS="entry"
ALIGN="LEFT"
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COLSPAN="1"
><P
CLASS="para"
>Stat field</P
></TH
><TH
CLASS="entry"
ALIGN="LEFT"
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COLSPAN="1"
><P
CLASS="para"
>Meaning</P
></TH
></TR
></THEAD
><TBODY
CLASS="tbody"
><TR
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VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-r</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File is readable by effective UID/GID</P
></TD
></TR
><TR
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VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-w</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File is writable by effective UID/GID</P
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-x</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File is executable by effective UID/GID</P
></TD
></TR
><TR
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VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-o</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode</P
></TD
><TD
CLASS="entry"
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COLSPAN="1"
><P
CLASS="para"
>File is owned by effective UID</P
></TD
></TR
><TR
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VALIGN="TOP"
><TD
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ROWSPAN="1"
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><P
CLASS="para"
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
></P
></TD
></TR
><TR
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VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-R</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File is readable by real UID/GID</P
></TD
></TR
><TR
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VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-W</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File is writable by real UID/GID</P
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-X</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File is executable by real UID/GID</P
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-O</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File is owned by real UID</P
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
></P
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-e</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File exists</P
></TD
></TR
><TR
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VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-z</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>size</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File has zero size</P
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-s</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>size</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File has nonzero size (returns size)</P
></TD
></TR
><TR
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VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
></P
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-f</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode,rdev</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File is a plain file</P
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-d</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode,rdev</P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>File is a directory</P
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
><CODE
CLASS="literal"
>-l</CODE
></P
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
><P
CLASS="para"
>mode</P
></TD