Re: named pipe for install

From: C.J. Jardine <cj10_at_cus.cam.ac.uk>
Date: Mon, 23 Aug 1993 09:54:03 GMT
Message-ID: <1993Aug23.095403.14078_at_infodev.cam.ac.uk>

I used the following script to read an Oracle installation tape on a remote tape drive (in this case, /dev/rst0 on a remote machine called bootes.cus).

DEF_T_REWIND='/dev/null'
DEF_T_NO_REWIND='/dev/null'
DEF_T_REWIND_CMD='rsh -l cj10 -n bootes.cus mt -f /dev/nrst0 rewind'
DEF_T_FORWARD_CMD='echo ignoring forward command'

tar()
{ rsh -l cj10 -n bootes.cus dd if=/dev/nrst0 | ( /bin/tar B$1 - ; cat >/dev/null) ; }
. ./oracle.boot

The slimy bit is the cat >/dev/null. This ensures that the dd is driven to end of file, which means that you are reliably positioned AFTER the closing tapemark. Local tar would leave you positioned BEFORE the tapemark - hence the dummy definition of DEF_T_FORWARD_CMD.

My first attempts, without the cat >/dev/null, left the tape unpredictably positioned, as it depended on a race between the dd on one machine and the tar on the other. Received on Mon Aug 23 1993 - 11:54:03 CEST