Installando MySQL da sorgente, su Slackware, lo script di default rc.mysqld (che fa riferimento a path "standard") non funziona... per questo si sono rese necessarie alcune modifiche per "parametrizzare" lo script e adattarlo alla propria installazione MySQL.

Ecco quello che sto usando:

#!/bin/sh
# Start/stop/restart mysqld.
#
# Copyright 2003 Patrick J. Volkerding, Concord, CA
# Copyright 2003 Slackware Linux, Inc., Concord, CA
#
# This program comes with NO WARRANTY, to the extent permitted by law.
# You may redistribute copies of this program under the terms of the
# GNU General Public License.

# To start MySQL automatically at boot, be sure this script is executable:
# chmod 755 /etc/rc.d/rc.mysqld

# Before you can run MySQL, you must have a database.  To install an initial
# database, do this as root:
#
#   su - mysql
#   mysql_install_db
#
# Note that step one is becoming the mysql user.  It's important to do this
# before making any changes to the database, or mysqld won't be able to write
# to it later (this can be fixed with 'chown -R mysql.mysql /var/lib/mysql').


MYSQLD_SAFE="/usr/local/mysql/bin/mysqld_safe"
PIDFILE="/usr/local/mysql-5.0.51a/var/homer.pid"
DATADIR="/usr/local/mysql-5.0.51a/var"


# To allow outside connections to the database comment out the next line.
# If you don't need incoming network connections, then leave the line
# uncommented to improve system security.
# SKIP="--skip-networking"

# Start mysqld:
mysqld_start() {
  if [ -x $MYSQLD_SAFE ]; then
    # If there is an old PID file (no mysqld running), clean it up:
    if [ -r $PIDFILE ]; then
      if ! ps axc | grep mysqld 1> /dev/null 2> /dev/null ; then
        echo "Cleaning up old /var/run/mysql/mysql.pid."
        rm -f $PIDFILE
      fi
    fi
    $MYSQLD_SAFE --datadir=$DATADIR --pid-file=$PIDFILE $SKIP &
  fi
}

# Stop mysqld:
mysqld_stop() {
  # If there is no PID file, ignore this request...
  if [ -r $PIDFILE ]; then
    killall mysqld
    # Wait at least one minute for it to exit, as we don't know how big the DB is...
    for second in 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 \
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 60 ; do
      if [ ! -r $PIDFILE ]; then
        break;
      fi
      sleep 1
    done
    if [ "$second" = "60" ]; then
      echo "WARNING:  Gave up waiting for mysqld to exit!"
      sleep 15
    fi
  fi
}

# Restart mysqld:
mysqld_restart() {
  mysqld_stop
  mysqld_start
}

case "$1" in
'start')
  mysqld_start
  ;;
'stop')
  mysqld_stop
  ;;
'restart')
  mysqld_restart
  ;;
*)
  echo "usage $0 start|stop|restart"
esac