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Full Discussion: cp output /dev/null results in not a directory
Top Forums UNIX for Dummies Questions & Answers cp output /dev/null results in not a directory Post 302318548 by stevesmo on Thursday 21st of May 2009 10:03:55 PM
Old 05-21-2009
cp output /dev/null results in not a directory
Hello,
I am working on a script to measure the read performance of a busybox environment. The logical choice is to use a command line like:

(time cp * /dev/null) 2> /tmp/howlong.txt

Ah, the rub is cp or /dev/null will only accept a single file at a time.
The result in the txt file is and output list that basically shows /dev/null/filename Not a directory.

I tried the same with using dd if=* of=/dev/null bs=1M, alas the results were similar.

I tried using a for loop, but I could not get time to work with syntax errors.

Example:

Works:
for FILE * cp $FILE /dev/null ; done

Fails:
(time for FILE * cp $FILE /dev/null ; done) 2> /tmp/howlong.txt

Any help here would be appreciated.
Thanks,

-Steve
 

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LEARN ABOUT NETBSD

lvdisplay

LVDISPLAY(8)						      System Manager's Manual						      LVDISPLAY(8)

NAME

       lvdisplay - display attributes of a logical volume

SYNOPSIS

       lvdisplay [-c|--colon] [-d|--debug] [-h|-?|--help] [--ignorelockingfailure] [--maps] [-P|--partial] [-v|--verbose] LogicalVolumePath [Logi-
       calVolumePath...]

DESCRIPTION

       lvdisplay allows you to see the attributes of a logical volume like size, read/write status, snapshot information etc.

       lvs (8) is an alternative that provides the same information in the style of ps (1).  lvs is recommended over lvdisplay.

OPTIONS

       See lvm for common options.

       -c, --colon
	      Generate colon separated output for easier parsing in scripts or programs.  N.B. lvs (8) provides considerably more control over the
	      output.

	      The values are:

	      * logical volume name
	      * volume group name
	      * logical volume access
	      * logical volume status
	      * internal logical volume number
	      * open count of logical volume
	      * logical volume size in sectors
	      * current logical extents associated to logical volume
	      * allocated logical extents of logical volume
	      * allocation policy of logical volume
	      * read ahead sectors of logical volume
	      * major device number of logical volume
	      * minor device number of logical volume

       -m, --maps
	      Display the mapping of logical extents to physical volumes and physical extents.

Examples
       "lvdisplay  -v  /dev/vg00/lvol2"  shows attributes of that logical volume.  If snapshot logical volumes have been created for this original
       logical volume, this command shows a list of all snapshot logical volumes and their status (active or inactive) as well.

       "lvdisplay /dev/vg00/snapshot" shows the attributes of this snapshot logical volume and also which original logical volume it is associated
       with.

SEE ALSO

       lvm(8), lvcreate(8), lvscan(8)

Sistina Software UK					 LVM TOOLS 2.02.44-cvs (02-17-09)					      LVDISPLAY(8)
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