From - Wed Aug 21 17:20:19 1996
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From: lgy@newton.phys.washington.edu (Laurence Yaffe)
Newsgroups: comp.sys.sgi.admin
Subject: Alternative "Backup" script avoiding 'bru'
Date: 18 Aug 1996 18:21:01 GMT
Organization: University of Washington
Lines: 174
Message-ID: <4v7mud$c6s@nntp5.u.washington.edu>
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    As many previous posts have noted, the fact that some of SGI's software
distributions exceed bru's pathetic 127 character pathname length limit is a
continuing nuisance for users of /usr/sbin/Backup or the backup GUIs.
But as Dave Olson repeatedly points out, /usr/sbin/Backup is just a
script so one can "easily" rewrite it to use a different backup program.

In the hope that it will benefit others, I offer below one such alternative
Backup script (also available as http://www.phys.washington.edu/~lgy/Backup).
It uses "cpio -H tar" to create tar-format archives, and has a command line
syntax which is upwardly-compatible with SGI's Backup.  It automatically
excludes active swap files and /proc files.

The strategy of using cpio to create tar-format archives was
dictated by my chosen requirements of:

0. Avoiding bru.

1. Supporting backup verification.
   (Eliminates dump and default-format cpio archives.)

2. Supporting incremental backups.
   (Eliminates tar for backup creation, since tar always descends recursively.)

3. Supporting multiple partition backups with a single command.
   (Also eliminates dump.)

One 'feature' of "cpio -H tar" is that it complains about files
whose UID or GID are missing from /etc/passwd or /etc/group.
Hence, running "find / -local \( -nouser -o -nogroup \) -print"
and fixing any such file ownership problems is recommended.

Comments or improvements welcome.

------------------------------------------------------------------------
Laurence G. Yaffe		yaffe@phys.washington.edu
Department of Physics
University of Washington	1-206-543-3902
------------------------------------------------------------------------
#!/bin/sh
#
#	Backup - perform file system backup
#
# Features:
#	Full or incremental (level 1) backups.
#	Backup verification (comparison of archive with existing disk files).
#	Creates tar-format archives.
#	Updates /etc/lastbackup on successful full backups.
#	Command line syntax compatible with SGI's /usr/sbin/Backup.
#       1024 character pathname length limit (instead of bru's limit of 127).
#
# System dependencies:
#	Archive creation requires a cpio accepting '-H tar'.	(IRIX, Solaris)
#	Archive verification requires a tar accepting 'C' key.	(IRIX only?)
#
# Environmental variables:
#	TAPE	   - tape device (/dev/tape default).
#	EXCLUSIONS - list of files to exclude from backup (space delimited).
#
# Laurence G. Yaffe (yaffe@phys.washington.edu)
#  8/14/96	- initial version

main()
{
prev=/etc/lastbackup			# marker for full backups
exclude=/tmp/excluded.$$		# exclusion tmp file
tape=${TAPE:-/dev/tape}			# tape device
fopt='-local ! -type s -print'		# find options
copt='-oa'				# cpio options

FLAGS="	-i		incremental backup
	-C		read archive and compare with disk
	-V		prints '.' for each file archived
	-v		prints name of each file archived
	-x		do not cross mount points
	-b<blks>	tape blocksize (in 512 byte blocks)
	-h<host>	remote tape drive host
	-f<tapedrive>	tape device to use
	-t<tapedrive>	same as -f"

USAGE="usage: Backup [<flags>] <dir|file> [<dir|file>] ...\n\nflags:$FLAGS"
NOPREV="No previous full backup, exiting."

while getopts CivVxb:f:h:t: opt
do
    case $opt in
    C)		cmpr=1 ;;		# archive comparison
    i)		incr=1 ;;		# incremental backup
    x)		xdev=1 ;;		# don't cross mount points
    b)		blks=$OPTARG ;;		# blocking factor
    h)		host=$OPTARG ;;		# remote host name
    f|t)	tape=$OPTARG ;;		# tape device
    v|V)	copt="$copt$opt" ;;	# verbosity level
    \?)		die "$USAGE" ;;
    esac
done
shift `expr $OPTIND - 1`

test "$host" && tape="${host}:$tape"
test "$blks" && copt="${copt} -C"`expr "$blks" \* 512`

if [ "$cmpr" ]					# compare with existing files
then
    tar Cf $tape "$@" | grep '^[?>!]'

else						# archive files to tape
    test -r "$1" || die "$USAGE"

    if   [ "$incr" ]				# incremental backup
    then
	test -f $prev && fopt="-newer $prev $fopt" || die "$NOPREV"

    elif [ "$xdev" ]				# filesystem limited backup
    then
	fopt="-mount $fopt"

    elif [ ."$1" = ./ ]				# full backup
    then
	date > $prev.new && full=1 || exit 1
    fi

    trap "rm -f $exclude" 0 1 2 15		# cleanup on exit

    exclusions > $exclude			# generate exclusions

    eval "find $@ $fopt | egrep -vf $exclude | cpio $copt -Htar -O$tape"

    status=$?

    test "$full" -a $status -eq 0 && roll $prev && allok

    exit $status
fi
}

exclusions()				# generated excluded file patterns
{
    for file in `swapfiles` $EXCLUSIONS
    do
	echo "^$file$"
    done
    echo '^/proc/'
    echo '^/dev/fd/'
    echo '^/var/adm/badlogin/'
}

swapfiles()				# find active swap files
{
    /etc/swap -l | while read pri file junk
    do
	test ! "$junk" -a -s $file && echo $file
    done
}

roll()
{
    test -f $1 && mv $1 $1.old ; mv $1.new $1
}

die()
{
    echo "$*" 1>&2 ; exit 1
}

allok()
{
    echo Full backup complete -- $prev updated 1>&2
}

main ${1+"$@"}
------------------------------------------------------------------------
Laurence G. Yaffe		yaffe@phys.washington.edu
Department of Physics
University of Washington	1-206-543-3902 (fax: 1-206-543-9523)