pax.html

unix 下的C开发手册,还用详细的例程。

<dt><b>-t</b>
<dd>Cause the access times of the archived files to be the same
as they were before being read by
<i>pax</i>.
<br>
<dt><b>-u</b>
<dd>Ignore files that are older (having a less recent
file modification time) than a pre-existing file or
archive member with the same name.
In read mode,
an archive
member with the same name as a file in the file system
will be extracted if the archive member is newer than the file.
In write mode,
an archive file member with the
same name as a file in the file system will be
superseded if the file is newer than the archive member.
It is unspecified if this is accomplished by actual
replacement in the archive or by appending to the archive.
In copy mode,
the file in the destination hierarchy will be replaced by the
file in the source hierarchy
or by a link to the file in the source hierarchy
if the file in the source hierarchy is newer.
<br>
<dt><b>-v</b>
<dd>In list mode,
produce a verbose table of contents (see the STDOUT section).
Otherwise, write archive member pathnames to standard error (see
the STDERR section).
<br>
<dt><b>-x&nbsp;</b><i>format</i>
<dd>
Specify the output archive format.
The
<i>pax</i>
utility recognises the following formats:
<dl compact>

<dt><b>cpio</b><dd>The extended
<i><a href="cpio.html">cpio</a></i>
interchange format; see the EXTENDED DESCRIPTION section.
The default
<i>blocksize</i>
for this format for character special archive files is 5120.
Implementations support all
<i>blocksize</i>
values less than or equal to 32256
that are multiples of 512.

<dt><b>ustar</b><dd>The extended
<i><a href="tar.html">tar</a></i>
interchange format; see the EXTENDED DESCRIPTION section.
The default
<i>blocksize</i>
for this format for character special archive files
is 10240.
Implementations support all
<i>blocksize</i>
values less than or equal to 32256
that are multiples of 512.

</dl>
<p>
Implementation-dependent formats will specify a default
block size as well as any other block sizes supported
for character special archive files.
<p>
Any attempt to append to an archive file in a format different
from the existing archive format will cause
<i>pax</i>
to exit immediately with a non-zero exit status.
<br>
<dt><b>-X</b>
<dd>When traversing the file hierarchy specified by a pathname,
<i>pax</i>
will not descend into directories that have a different device ID
(<b>st_dev</b>,
see the <b>XSH</b> specification
<i><a href="../xsh/stat.html">stat()</a></i>).
<p>
</dl>
<p>
The options that operate on the names of files or archive members
(<b>-c</b>,
<b>-i</b>,
<b>-n</b>,
<b>-s</b>,
<b>-u</b>
and
<b>-v</b>)
interact as follows.
In read mode, the archive members are selected
based on the user-specified
<i>pattern</i>
operands as modified by the
<b>-c</b>,
<b>-n</b>
and
<b>-u</b>
options.
Then, any
<b>-s</b>
and
<b>-i</b>
options will modify, in that order,
the names of the selected files.
The
<b>-v</b>
option will write
names resulting from these modifications.
<p>
In write mode, the
files are selected based on the user-specified pathnames as
modified by the
<b>-n</b>
and
<b>-u</b>
options.
Then, any
<b>-s</b>
and
<b>-i</b>
options will, in that order, modify the names of these selected files.
The
<b>-v</b>
option will write names resulting from these modifications.
<p>
If both the
<b>-u</b>
and
<b>-n</b>
options are specified,
<i>pax</i>
does not consider a file selected unless it is newer than the file to
which it is compared.
</blockquote><h4><a name = "tag_001_014_1692">&nbsp;</a>OPERANDS</h4><blockquote>
The following operands are supported:
<dl compact>

<dt><i>directory</i><dd>
The destination directory pathname for copy mode.

<dt><i>file</i><dd>A pathname of a file to be copied or archived.

<dt><i>pattern</i><dd>A pattern matching one or more pathnames of archive members.
A pattern must be given in the name-generating notation
of the pattern matching notation in
<xref href=patmat><a href="chap2.html#tag_001_013">
Pattern Matching Notation
</a></xref>,
including the filename expansion rules in
<xref href=patfilx><a href="chap2.html#tag_001_013_003">
Patterns Used for Filename Expansion
</a></xref>.
The default, if no
<i>pattern</i>
is specified, is
to select all members in the archive.

</dl>
</blockquote><h4><a name = "tag_001_014_1693">&nbsp;</a>STDIN</h4><blockquote>
In write mode,
the standard input is used only if no
<i>file</i>
operands are specified.
It must be a text file containing a list of pathnames, one per line,
without leading or trailing
blank characters.
<p>
In list and read modes,
the standard input
must be an archive file.
<p>
Otherwise, the standard input will not be used.
</blockquote><h4><a name = "tag_001_014_1694">&nbsp;</a>INPUT FILES</h4><blockquote>
The input file named by the
<i>archive</i>
option-argument,
or standard input when the archive is read from there,
will be a file formatted according to
one of the specifications in the EXTENDED DESCRIPTION section
or some other, implementation-dependent, format.
<p>
The file
<b>/dev/tty</b>
is used to write prompts and read responses.
</blockquote><h4><a name = "tag_001_014_1695">&nbsp;</a>ENVIRONMENT VARIABLES</h4><blockquote>
The following environment variables affect the execution of
<i>pax</i>:
<dl compact>

<dt><i>LANG</i><dd>Provide a default value for the internationalisation variables
that are unset or null.
If
<i>LANG</i>
is unset or null, the corresponding value from the
implementation-dependent default locale will be used.
If any of the internationalisation variables contains an invalid setting, the
utility will behave as if none of the variables had been defined.

<dt><i>LC_ALL</i><dd>
If set to a non-empty string value,
override the values of all the other internationalisation variables.

<dt><i>LC_COLLATE</i><dd>
Determine the locale for the
behaviour of ranges, equivalence classes
and multi-character collating elements
used in the
pattern matching expressions for the
<i>pattern</i>
operand, the basic regular expression for the
<b>-s</b>
option, and the
extended regular expression defined for the
<b>yesexpr</b>
locale keyword in the LC_MESSAGES category.

<dt><i>LC_CTYPE</i><dd>
Determine the
locale for the interpretation of sequences of bytes of text data as
characters (for example, single- as opposed to multi-byte characters
in arguments and input files),
the behaviour of character classes
used in the extended regular expression defined for the
<b>yesexpr</b>
locale keyword in the LC_MESSAGES category,
and pattern matching.


<dt><i>LC_MESSAGES</i><dd>
Determine the locale for the processing of affirmative responses
that should be used to affect the format and contents of diagnostic
messages written to standard error.

<dt><i>LC_TIME</i><dd>
Determine the format and contents of date and time strings when the
<b>-v</b>
option is specified.

<dt><i>NLSPATH</i><dd>
Determine the location of message catalogues
for the processing of
<i>LC_MESSAGES .
</i>
</dl>
</blockquote><h4><a name = "tag_001_014_1696">&nbsp;</a>ASYNCHRONOUS EVENTS</h4><blockquote>
Default.
</blockquote><h4><a name = "tag_001_014_1697">&nbsp;</a>STDOUT</h4><blockquote>
In write mode, if
<b>-f</b>
is not specified, the
standard output will be the archive
formatted according to
one of the specifications in the EXTENDED DESCRIPTION section,
or some other implementation-dependent format.
(See
<b>-x</b>&nbsp;<i>format</i>.)
<p>
In list mode, the
table of contents of the selected archive members will be written to
standard output using the following format:
<code>
<p>
<tt>"%s\n"</tt>, &lt;<i>pathname</i>&gt;
</code>
<p>
If the
<b>-v</b>
option is specified in list mode, the table of contents of the selected
archive members will be written to standard output using the
following formats:
<p>
For pathnames representing hard links to previous members of the archive:
<code>
<p>
<tt>"%s<img src="../images/delta.gif" border=0>==<img src="../images/delta.gif" border=0>%s\n"</tt>, &lt;<i>ls -l listing</i>&gt;,
&lt;<i>linkname</i>&gt;
</code>
<p>
For all other pathnames:
<code>
<p>
<tt>"%s\n"</tt>, &lt;<i>ls -l listing</i>&gt;
</code>
<p>
where
&lt;<i>ls -l listing</i>&gt;
is the format specified by the
<i><a href="ls.html">ls</a></i>
utility
with the
<b>-l</b>
option.
When writing pathnames in this format, it is
unspecified what is written for fields for which the
underlying archive format does not have the correct information,
although the correct number of
blank-character-separated
fields will be written.
<p>
In list mode,
standard output will not be buffered more than a line at a time.
</blockquote><h4><a name = "tag_001_014_1698">&nbsp;</a>STDERR</h4><blockquote>
If
<b>-v</b>
is specified in read, write or copy modes,
<i>pax</i>
will write the
pathnames it processes to the standard error output using the
following format:
<code>
<p>
<tt>"%s\n"</tt>, &lt;<i>pathname</i>&gt;
</code>
<p>
These pathnames will be written as soon as processing is begun
on the file or archive member, and will be flushed to standard error.
The trailing
newline character,
which will not be buffered,
will be written when the file has been read or written.
<p>
If the
<b>-s</b>
option is specified, and the replacement string has
a trailing
p,
substitutions will be written to
standard error in the following format:
<code>
<p>
<tt>"%s<img src="../images/delta.gif" border=0>&gt;&gt;<img src="../images/delta.gif" border=0>%s\n"</tt>, &lt;<i>original pathname</i>&gt;,
&lt;<i>new pathname</i>&gt;
</code>
<p>
In all operating modes of
<i>pax</i>,
optional messages of unspecified format concerning
the input archive format and volume number,
the number
of files, blocks, volumes and media parts as well as other
diagnostic messages may be written to standard error.
<p>
In all formats, for both standard output and standard error, it is
unspecified how non-printable characters in pathnames or linknames
are written.
</blockquote><h4><a name = "tag_001_014_1699">&nbsp;</a>OUTPUT FILES</h4><blockquote>
In read mode,
the extracted or copied output
files are of the archived file type.
<p>
In write mode, the
output file named by the
<b>-f</b>
option-argument is a file
formatted according to one of the specifications in
the EXTENDED DESCRIPTION section,
or some other, implementation-dependent format.
</blockquote><h4><a name = "tag_001_014_1700">&nbsp;</a>EXTENDED DESCRIPTION</h4><blockquote>
<h5><a name = "tag_001_014_1700_001">&nbsp;</a>Extended cpio Format</h5>
The octet-oriented
<i><a href="cpio.html">cpio</a></i>
archive format is a series of entries,
each comprising a header
that describes the file, the name of the file and then the
contents of the file.
<p>
An archive may be recorded as a series of fixed-size blocks of octets.
This blocking will be used only to make physical
I/O
more efficient.
The last group of blocks always will be at the full size.
<p>
For the
octet-oriented
<i><a href="cpio.html">cpio</a></i>
archive format, the individual entry
information will be in the order indicated and described by
the following table:
<pre>
<table  bordercolor=#000000 border=1 align=center><tr valign=top><th align=center><b>Header Field Name</b>
<th align=center><b>Length (in Octets)</b>
<th align=center><b>Interpreted as</b>
<tr valign=top><td align=left><b>c_magic</b>
<td align=left>6
<td align=left>Octal number
<tr valign=top><td align=left><b>c_dev</b>
<td align=left>6
<td align=left>Octal number
<tr valign=top><td align=left><b>c_ino</b>
<td align=left>6
<td align=left>Octal number
<tr valign=top><td align=left><b>c_mode</b>
<td align=left>6
<td align=left>Octal number
<tr valign=top><td align=left><b>c_uid</b>
<td align=left>6
<td align=left>Octal number
<tr valign=top><td align=left><b>c_gid</b>
<td align=left>6
<td align=left>Octal number
<tr valign=top><td align=left><b>c_nlink</b>
<td align=left>6
<td align=left>Octal number
<tr valign=top><td align=left><b>c_rdev</b>
<td align=left>6
<td align=left>Octal number
<tr valign=top><td align=left><b>c_mtime</b>
<td align=left>11
<td align=left>Octal number
<tr valign=top><td align=left><b>c_namesize</b>
<td align=left>6
<td align=left>Octal number
<tr valign=top><td align=left><b>c_filesize</b>
<td align=left>11
<td align=left>Octal number
<tr valign=top><th align=left><b>Filename Field Name</b>
<th align=left>Length
<th align=left>Interpreted as
<tr valign=top><td align=left><b>c_name</b>
<td align=left>c_namesize
<td align=left>Pathname string
<tr valign=top><th align=left><b>File Data Field Name</b>
<th align=left>Length
<th align=left>Interpreted as
<tr valign=top><td align=left><b>c_filedata</b>
<td align=left>c_filesize