:
##########################################################################
# Title      :	getpic - background picture for X11 with xv
# Author     :	Heiner Steven (heiner.steven@odn.de)
#		(based on a script by muftix@asbach.de)
# Date       :	1995-03-07
# Requires   :	cfcat, rand
# Category   :	Desktop
# SCCS-Id.   :	@(#) getpic	2.1 04/03/12
##########################################################################
# Description
#	Prints name of a background image
##########################################################################

PN=`basename "$0"`			# program name
VER='2.1'

: ${GREP:=egrep}

# Directories to search for pictures
: ${PICDIRS:="$HOME/pictures:/export/pictures:/usr/local/pictures"}
: ${PICEXCL:=$HOME/.picexclude}		# exclude list
: ${PICDEF:=`cfcat $HOME/.picdefault 2>/dev/null`}	# Default image

usage () {
    echo >&2 "$PN - print name of a background picture, $VER
usage: $PN [picture|pattern]

If no picture is specified, one is chosen randomly. Otherwise a picture
is chosen randomly chosen from all files matching the specified pattern.

Environment variables:
    Directory to search
	   for pictures: PICDIRS=$PICDIRS
    Pictures to exclude: PICEXCL=$PICEXCL
    Name of default picture: PICDEV=$PICDEF"
    exit 1
}

msg () {
    for i
    do echo "$PN: $i" >&2
    done
}

fatal () { msg "$@"; exit 1; }

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

[ -f "$PICEXCL" ] || > $PICEXCL
[ -f "$PICDEF" ] || echo "# default picture for $PN" > $HOME/.picdefault

Pic=$PICDEF
PicList=${TMPDIR:=/tmp}/gp$$.l
Tmp=$TMPDIR/gp$$.t
 
# Remove temporary file at exit or interrupt
trap 'rm -f "$PicList" "$Tmp" > /dev/null 2>&1' 0
trap "exit 2" 1 2 3 15

# Create picture list and return count
for dir in `echo "$PICDIRS" | tr : ' '`
do
    find "$dir" -type f -print 2>/dev/null |
	fgrep -v -f "$PICEXCL"
done > "$PicList" 

if [ $# -gt 0 ]
then					# try to get specified picture
    # Select the matching pictures
    "$GREP" "$1" "$PicList" > "$Tmp" && mv "$Tmp" "$PicList" || exit 1
fi

# Count images (lines), remove leading blanks
n=`echo \`wc -l < "$PicList"\``
if [ ${n:=0} -gt 0 ]
then					# randomly select picture
    # Randomly choose one picture 
    k=`rand "$n"`
    Pic=`sed -ne "${k}{p;q;}" "$PicList"`
    if [ -r "$Pic" ]
    then
	msg "selected #$k of $n pictures: $Pic"
    else
    	msg "could not read file $Pic - using default"
    	Pic=$PICDEF
    fi
fi

[ -z "$Pic" ] && fatal "could not determine picture"

cat <<EOT
$Pic
EOT