AIX

sed 's/^/# /' <filename>

sed 's/^# //' <filename>

#! /bin/ksh

# run this as root. Call the script in the form
#
#     script [-c|-u] <username>
#
#    -c comment out crontab for <username>
#    -u uncomment crontab for <username>
#
#   default behavior is "-c", <username> is obligatory


typeset    chDirection="comment"
typeset    chUser=""
typeset    fTmpFile="/tmp/$$"

if [ "$1" = "-c" ] ; then
     chDirection="comment"
     shift
elif [ "$1" = "-u" ] ; then
     chDirection="uncomment"
     shift
fi

if [ $(lsuser "$1" ; print - $?) -gt 0 ] ; then
     print -u2  "The user account $1 does not exist"
     exit 1
else
     chUser="$1"
     shift
fi

if [ ! -f /var/spool/cron/crontab/${chUser} ] ; then
     print -u2 "User $chUser has no crontab file."
     exit 2
fi

if [ "$chDirection" = "comment" ] ; then
     sed 's/^/# /' /var/spool/cron/crontab/${chUser} > $fTmpFile
fi
if [ "$chDirection" = "uncomment" ] ; then
     sed 's/^# //' /var/spool/cron/crontab/${chUser} > $fTmpFile
fi
mv $fTmpFile var/spool/cron/crontab/${chUser}

exit 0