On 11/05/2013 07:34 PM, Nico Kadel-Garcia wrote: > On Tue, Nov 5, 2013 at 7:35 PM, Yasha Karant<[log in to unmask]> wrote: >> I have not tried this yet, but the statement is that "The cmp utility >> compares two files of any type and writes the results to the standard >> output." >> >> Will this work for mount points or device special files that are mounted on >> mount points, allowing one to compare two full directory tree hierarchies? > > Yup! The idea that "a file is a file, even when it's a mountpoint or a > symlink or a pipe or a socket" is fundamental to the concept of what a > "file" is in libc and in the kernel. itself. > >> That is, using the situation elaborated below (that is, earlier in this >> thread), will >> >> cmp /dev/loop0 /dev/sr0 > > Should work, if those are the valid device names. If you can 'md5sum' > it, you can 'cmp' it. > I use the following 'rawread' script to compare my ISO to burned media. It is then run through a hash algorithm (md5, sha, etc) to compare. the RAW_DEV should be the device node associated with the optical drive. #!/bin/sh if [ -n "$1" ] ; then RAW_DEV=$1 fi blocksize=`isoinfo -d -i $RAW_DEV | grep "^Logical block size is:" | cut -d " " -f 5` if test "$blocksize" = ""; then echo "FATAL ERROR: Blank blocksize" >&2 exit fi blockcount=`isoinfo -d -i $RAW_DEV | grep "^Volume size is:" | cut -d " " -f 4` if test "$blockcount" = ""; then echo "FATAL ERROR: Blank blockcount" >&2 exit fi dd if=$RAW_DEV bs=$blocksize count=$blockcount conv=notrunc,noerror Here is the portion comparison script, that calls 'rawread': # Get the iso MD5 echo "Generating MD5 for $TARGET_FILE..." ISO_MD5=`md5sum $TARGET_FILE | cut -d " " -f 1` # Get the disc MD5 echo "Generating MD5 for CD/DVD..." DISC_MD5=`${CDREC_DIR}/rawread $RAW_DEV | md5sum | cut -d " " -f 1` echo "" echo "ISO MD5: $ISO_MD5" echo "DISC MD5: $DISC_MD5" echo "" echo -n "Verification: " if [ "$ISO_MD5" = "$DISC_MD5" ] ; then echo "PASSED" exit 0 else echo "FAILED" exit 1 fi I have been using this long before I used any gui burning utilities. It has a good track record for me. Extracting the ISO information and using the above dd options should catch any media errors occurring. -Mark -- Mr. Mark V. Stodola Senior Control Systems Engineer National Electrostatics Corp. P.O. Box 620310 Middleton, WI 53562-0310 USA Phone: (608) 831-7600 Fax: (608) 831-9591