RRDTool Command:

/usr/bin/rrdtool graph - \
--imgformat=PNG \
--start=-86400 \
--end=-300 \
--title="Frontend 1 - Apache Statistics - Bytes / Request" \
--base=1024 \
--height=120 \
--width=500 \
--alt-autoscale-max \
--lower-limit=0 \
--vertical-label="bytes / hit" \
--slope-mode \
DEF:a="/var/www/html/graficas/rra/frontend_1_apache_total_hits_113.rrd":apache_total_kbytes:AVERAGE \
DEF:b="/var/www/html/graficas/rra/frontend_1_apache_total_hits_113.rrd":apache_total_hits:AVERAGE \
CDEF:cdefa=a,UN,0,a,100000,GT,0,a,IF,IF \
CDEF:cdefb=b,UN,0,b,100000,GT,0,b,IF,IF \
CDEF:cdefc=cdefb,0,EQ,0,cdefa,1024,*,cdefb,/,IF,0,1000000,LIMIT \
CDEF:cdefg=a,0,0,LIMIT \
CDEF:cdefba=b,0,0,LIMIT \
COMMENT:""  \
COMMENT:""  \
AREA:cdefc:"Bytes / Request"  \
GPRINT:cdefc:LAST:"Current\:%8.2lf %s"  \
GPRINT:cdefc:AVERAGE:"Average\:%8.2lf %s"  \
GPRINT:cdefc:MAX:"Maximum\:%8.2lf %s\n"  \
LINE2:cdefg#FF0000:"kBytes"  \
GPRINT:a:LAST:"         Current\:%8.2lf %s"  \
GPRINT:b:AVERAGE:"Average\:%8.2lf %s"  \
GPRINT:b:MAX:"Maximum\:%8.2lf %s\n"  \
LINE2:cdefba#00FF00:"Hits"  \
GPRINT:b:LAST:"           Current\:%8.2lf %s"  \
GPRINT::AVERAGE:"Average\:%8.2lf %s"  \
GPRINT::MAX:"Maximum\:%8.2lf %s\n"  \
COMMENT:"                            Represents the number of bytes per hit\n"  \
COMMENT:"                             based on ApacheStats v0.4 - Rolf Poser\n" 

RRDTool Says:

ERROR: Expected some arguments after 'COMMENT:'