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Full Discussion: Perl - backticks v system in if statements
Top Forums Shell Programming and Scripting Perl - backticks v system in if statements Post 79740 by ErNci on Sunday 31st of July 2005 06:25:47 AM
Old 07-31-2005
Yes, as tjlist said, the percecitonal way really should be

if ( ( system("/bin/chio -f $changerDevice move slot ".($tape-1)." drive 0
") ) / 256 ) {
print "$progname: cannot '/bin/chio -f $changerDevice move' tape
$tape into drive 0\n";
exit(2);
}
print LOG &do_time(), ": leave: Load\n";

And in the first example, the 2nd example would be

sub getDate {
print "start date\n";
my $buff = '';
if ( ($buff = `/bin/date`) eq ''){
print "can't get date\n";
exit(2);
}
print "finish date\n";
}
 

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LEARN ABOUT V7

restor

RESTOR(1M)																RESTOR(1M)

NAME

       restor - incremental file system restore

SYNOPSIS

       restor key [ argument ... ]

DESCRIPTION

       Restor  is  used  to  read magtapes dumped with the dump command.  The key specifies what is to be done.  Key is one of the characters rRxt
       optionally combined with f.

       f      Use the first argument as the name of the tape instead of the default.

       r or R The tape is read and loaded into the file system specified in argument.  This should not be done lightly (see below).  If the key is
	      R  restor  asks which tape of a multi volume set to start on.  This allows restor to be interrupted and then restarted (an icheck -s
	      must be done before restart).

       x      Each file on the tape named by an argument is extracted.	The file name has all `mount' prefixes removed; for example,  /usr/bin/lpr
	      is  named  /bin/lpr  on the tape.  The file extracted is placed in a file with a numeric name supplied by restor (actually the inode
	      number).	In order to keep the amount of tape read to a minimum, the following procedure is recommended:

	      Mount volume 1 of the set of dump tapes.

	      Type the restor command.

	      Restor will announce whether or not it found the files, give the number it will name the file, and rewind the tape.

	      It then asks you to `mount the desired tape volume'.  Type the number of the volume you choose.  On a multivolume  dump  the  recom-
	      mended  procedure  is  to mount the last through the first volume in that order.	Restor checks to see if any of the files requested
	      are on the mounted tape (or a later tape, thus the reverse order) and doesn't read through the tape if no files  are.   If  you  are
	      working with a single volume dump or the number of files being restored is large, respond to the query with `1' and restor will read
	      the tapes in sequential order.

	      If you have a hierarchy to restore you can use dumpdir(1) to produce the list of names and a shell  script  to  move  the  resulting
	      files to their homes.

       t      Print the date the tape was written and the date the filesystem was dumped from.

       The r option should only be used to restore a complete dump tape onto a clear file system or to restore an incremental dump tape onto this.
       Thus

	    /etc/mkfs /dev/rp0 40600
	    restor r /dev/rp0

       is a typical sequence to restore a complete dump.  Another restor can be done to get an incremental dump in on top of this.

       A dump followed by a mkfs and a restor is used to change the size of a file system.

FILES

       default tape unit varies with installation
       rst*

SEE ALSO

       dump(1), mkfs(1), dumpdir(1)

DIAGNOSTICS

       There are various diagnostics involved with reading the tape and writing the disk.  There are also diagnostics if the i-list  or  the  free
       list of the file system is not large enough to hold the dump.

       If the dump extends over more than one tape, it may ask you to change tapes.  Reply with a new-line when the next tape has been mounted.

BUGS

       There is redundant information on the tape that could be used in case of tape reading problems.	Unfortunately, restor doesn't use it.

																	RESTOR(1M)
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