Listing 1 backup

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# Listing 1:
# Shellscript:    backup - backup (remote) system on local tape
# Author     :    Heiner Steven <heiner.steven@odn.de>
# Requires   :    cpio, find, {rsh | ssh}
# Category   :    System Administration
# SCCS-Id.   :    @(#) backup    1.1 03/05/29
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# Description
#
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PN=`basename "$0"`                       # Program name
VER='1.1'

# Variables written in UPPER CASE can be set in the environment before
# invoking this script. The following lines set default values if the
# variables were not set:

: ${TAPE:=/dev/rmt0}                     # Local tape device

# Program to run a command remotely. Should have the syntax
# $RCMD $RCMDFLAGS host command [...]

: ${RCMD:=rsh}                           # Remotely run command
: ${RCMDFLAGS="-l root"}
#: ${RCMD:=ssh}                          # Use "ssh"
#: ${RCMD:="-l root"}                    # Use "ssh"

usage () {
    echo >&2 "$PN - backup (remote) system on local tape, $VER
usage: $PN rhost [directory ...]

The specified directories (default: all) on the host \"rhost\" are
combined into an \"cpio\" archive, which then is written to a local
tape device ($TAPE)."
    exit 1
}

set -- `getopt :h "$@"` || usage
[ $# -lt 1 ] && usage                    # "getopt" detected an error

while [ $# -gt 0 ]
do
    case "$1" in
                    # your flags here
    --)    shift; break;;
    -h)    usage;;
    -*)    usage;;
    *)    break;;                        # First host name
    esac
    shift
done

[ $# -gt 0 ] || set -- localhost         # Default remote host
Rhost=$1; shift
[ $# -gt 0 ] || set -- '.[!.]* .'        # Default remote directory pattern

if [ -c "$TAPE" -o -b "$TAPE" ]          # Is $TAPE a valid device?
then
    echo >&2 "Write directories from $Rhost to local device $TAPE (^d = no)? \c"
    read dummy || { echo >&2; exit 0; }
else
    echo >&2 "cannot access backup device TAPE=$TAPE"
    exit 1
fi

if [ X`$RCMD $RCMDFLAGS "$Rhost" pwd` != X ]    # Try rsh/ssh
then
    # Create a remote "cpio" archive, and send it over the net to a
    # local "dd" process, that writes it to the tape device.

    set -x
    "$RCMD" $RCMDFLAGS "$Rhost" 'cd /; find '"$*"' -xdev -print |
    cpio -ov -H odc' |
    dd of=$TAPE obs=10k
    set +x
else
    echo >&2 "$PN: cannot reach host $Rhost (.rhosts entry for root?)"
    echo >&2 "$PN: Please verify that \"$RCMD $RCMDFLAGS $Rhost pwd\" works"
    exit 1
fi