#!/bin/ksh
#	@(#)	Work with crontab
#..#	systems: 
#..#	sites: 
#..#    level:
#..#    publish:	y
#..#    keys:
#..#    date:
#..#    vers:           1.4     25/Nov/2005-12:57


[ $0 = ${0#/} ] && this=$(pwd -H)/$0 || this=$0
tag=${0##*/}
tmp=/tmp/${tag}$$
#rm -f $tmp*
find /tmp -xdev -name "${tag}*.sav" -mtime +1 -exec rm {} \; 2>/dev/null &

usage="Usage: $tag [-w] [-m] <job>"

while [ $# -gt 0 ]; do
	case "$1" in
	-v|-x)	set "$1" ;;
	-vi)    lockvi $this; exit ;;
	-view)  view $this; exit ;;
	-about)
		echo "$tag was written by David Ledger"
		echo "dledger@ivdcs.co.uk"
		echo "Free to use at your own risk"
		echo "Copyright 2005"
		exit ;;
	-ver)
		ver=$(egrep '#..#[      ]*vers:' $this)
		ver=${ver#"${ver%%[1-9]*}"}
		print ${ver%%[!0-9.]*}
		exit ;;
	-h)
		echo ""
		echo "$usage"
		echo ""
		echo "$tag edits a users crontab file, changing the first line"
		echo "that would be found by an 'ed' /<job>/ search.  The time"
		echo "on that line is changed to be 1 minute ahead of the"
		echo "current time.  If '-w' is given, after the edit and re-"
		echo "submission to cron, the script sleeps until the next"
		echo "minute before exiting.  If '-m' is specified, the same"
		echo "wait is made, and after a further two seconds, 'mailx' is"
		echo "invoked to read the mail resulting from the cron job."
		echo ""
		echo "As well as changing the minute and hour fields, $tag"
		echo "changes the day, month and weekday fields to today, so"
		echo "that test entries will not run every day, but only at the"
		echo "requested date/time in years when the weekday also"
		echo "matches."
		echo ""
		echo ""
		exit ;;
	-w*)	wait=1 ;;
	-m*)	wait=1; mail=1 ;;
	*)
		job="$(echo "$1" | sed 's,/,\\/,')"
		;;
	esac
	shift
done

[ "$job" ] || { print "$usage"; print "Need to specify cron job"; exit; }

nxtmin() {
	set -A nm $*
	[ ${nm[4]} -lt 59 ] && nm[4]=$((nm[4] + 1)) || {
		[ ${nm[3]} -lt 23 ] && {
			nm[3]=$((nm[3] + 1))
			nm[4]=0
		} || {
			nm[3]=0
			nm[4]=0
		}
	}
	echo ${nm[*]}
}

set -A dt `date "+%y %m %d %H %M %S %u"`

[ ${dt[5]} -gt 58 ] && {
	sleep 2
	set -A dt `date "+%y %m %d %H %M %S"`
}

echo ${dt[*]}
set -A nm `nxtmin ${dt[*]}`

crontab -l > $tmp
cp ${tmp} ${tmp}.sav && print -u2 "Copy of existing saved as ${tmp}.sav" || exit
ed $tmp <<FrEd
/^[^#].*$job/p
.t.
-
s/^/#/
+
s/^[0-9*][0-9]* [0-9*][0-9]* [0-9*][0-9]* [0-9*][0-9]* [0-9*][0-9]*/${nm[4]} ${nm[3]} ${dt[2]} ${dt[1]} $((${dt[6]} % 7))/p
w
q
FrEd

#cat $tmp
crontab $tmp

[ "$wait" ] && sleep $((60 - dt[5]))

[ "$mail" ] && sleep 5 && mailx